The Iran–Iraq War, also called the First Imposed War, Eight-Year War, or Sacred Defense by Iran, began with the Iraqi invasion of Iran in September 1980. After eight years of conflict, both countries accepted a ceasefire deal brokered by the United Nations, which became effective in August 1988. The war caused around 500,000 deaths (excluding numbers from the related Anfal campaign), making it the deadliest conventional war ever fought between regular armies of developing countries. In starting the war, the Iraqi government—led by President Saddam Hussein—primarily wanted to prevent Ruhollah Khomeini, Iran's leader following the 1979 Iranian Revolution, from exporting Iran's new state ideology to Iraq. Iraq also feared that Iran, being a theocratic state mostly composed of Shia Muslims, would rally Iraq's Shia majority against the Sunni Muslim-controlled Baʽathist government. Iraq also wished to replace Iran as the main national power in the Persian Gulf. The war followed a long-running history of border disputes between the two states, as a result of which Iraq planned to retake the eastern bank of the Shatt al-Arab river that it had ceded to Iran in the 1975 Algiers Agreement. The conflict involved large-scale trench warfare, and deliberate attacks on civilians, including Iraqi chemical attacks. At the start of the war, Iraq expected a decisive victory, considering Iran's post-revolutionary chaos, but their invasion had stalled by December 1980. The Iranian military then gained momentum, and recaptured all their territory by June 1982. Having pushed Iraqi forces back to the pre-war borders, Iran launched an invasion of Iraq, which created a five-year offensive. In mid-1988, Iraq launched a series of counter-offensives that created the military stalemate present at the war's end. Iraq was aided by the National Council of Resistance of Iran, the United States, the United Kingdom, the Soviet Union, France, Italy, Yugoslavia, and most Arab countries. Iran was aided by the Kurdistan Democratic Party, the Patriotic Union of Kurdistan, Syria, Libya, North Korea, China, South Yemen, Pakistan, Cuba, and Israel. Meanwhile, Iraqi support for Arab separatists in Iran increased. After years of military and economic losses, decreasing morale, intensifying Iran–U.S. relations, and little international action against Iraqi attacks on Iranian civilians, Iran agreed to a ceasefire with Iraq under United Nations Security Council Resolution 598. The war did not create any permanent border changes, and neither country received war reparations afterwards. Both sides suffered financially. They continued engaging in low-level military conflict until relations improved following Saddam's overthrow in 2003.
Background
Iran–Iraq relations
In 1937, Iran and Iraq signed a treaty to settle their dispute over control of the Shatt al-Arab river; they agreed that Iranian ships had to pay tolls when they used the river. In 1969, Iran broke the treaty, as their ships no longer paid the tolls. The Shah of Iran argued that the treaty had been unfair. Iraq threatened war, but did nothing at this time, as their weaker military became threatened when Iranian naval forces sailed down the Shatt al-Arab in a show of force. The new Iraqi–Iranian tensions led to significant bloodshed, which lasted until the 1975 Algiers Agreement, when Iraq ceded to Iran the eastern bank of the river. Their relations briefly improved in 1978, when Iranian agents in Iraq discovered plans for a pro-Soviet coup d'état against Iraq's government. When informed of this plot, Iraq's president Saddam Hussein ordered the execution of dozens of his army's officers, and expelled Ruhollah Khomeini from Iraq, who led clerical opposition to the Shah.
After the Iranian Revolution
Tensions between Iraq and Iran were fuelled by Iran's Islamic revolution and its appearance of being a Pan-Islamic force, in contrast to Iraq's Arab nationalism. Despite Iraq's goal of regaining the Shatt al-Arab, the Iraqi government initially seemed to welcome the Iranian revolution, which overthrew Shah Mohammad Reza Pahlavi, who was seen as a common enemy. There were frequent clashes along the Iran–Iraq border throughout 1980. Khomeini called on Iraqis to overthrow the Ba'ath government, which was received with considerable anger in Baghdad. In July 1979, despite Khomeini's call, Saddam gave a speech praising the Iranian Revolution and called for an Iraqi–Iranian friendship based on non-interference in each other's internal affairs. When Khomeini rejected Saddam's overture by calling for Islamic revolution in Iraq, Saddam was alarmed. Iran's new Islamic administration was regarded in Baghdad as an irrational, existential threat to the Ba'ath government, especially because the Ba'ath party, having a secular nature, discriminated against and posed a threat to the fundamentalist Shia movement in Iraq, whose clerics were Iran's allies within Iraq and whom Khomeini saw as oppressed. In April 1980, the Islamic Dawa Party, an Iraqi Islamist group with supportive ties to Iran, attempted to assassinate Tariq Aziz, a high ranking Ba'athist and Iraq's deputy prime minister, in retaliation for a March decree declaring "membership of Dawa [to be] a capital offense". The attempt failed and instead killed several students. Three days later, the funeral procession for the dead students was bombed. This failed assassination plot, carried out by an Iran-backed group, formed a part of Iraq's casus belli for the invasion of Iran. Iraq's immediate response was to order the execution of Muhammad Baqir al-Sadr, an Iraqi Shi'ite cleric seen as the public face of the Dawa movement, along with al-Sadr's sister. On 30 April, Iraq organised an attack on the Iranian embassy in London. Saddam's primary interest in war may have also stemmed from his desire to right the supposed "wrong" of the Algiers Agreement, in addition to finally achieving his desire of becoming the regional superpower. Saddam's goal was to supplant Egypt as the "leader of the Arab world" and to achieve hegemony over the Persian Gulf. He saw Iran's increased weakness due to revolution, sanctions, and international isolation. Saddam had invested heavily in Iraq's military since his defeat against Iran in 1975, buying large amounts of weaponry from the Soviet Union and France. Between 1973 and 1980, Iraq purchased numerous tanks and Soviet-made aircraft. By 1980, Iraq possessed 242,000 soldiers, second only to Egypt in the Arab world, 2,350 tanks and 340 combat aircraft. Watching the disintegration of the Iranian army, he saw an opportunity to attack, using the threat of Islamic Revolution as a pretext. Iraqi military intelligence reported in July 1980 that despite Iran's bellicose rhetoric, "it is clear that, at present, Iran has no power to launch wide offensive operations against Iraq, or to defend on a large scale." Days before the Iraqi invasion and in the midst of rapidly escalating cross-border skirmishes, Iraqi military intelligence again reiterated on 14 September that "the enemy deployment organization does not indicate hostile intentions and appears to be taking on a more defensive mode". On 8 March 1980, Iran announced it was withdrawing its ambassador from Iraq, downgraded its diplomatic ties to the charge d'affaires level, and demanded that Iraq do the same. The following day, Iraq declared Iran's ambassador persona non grata, and demanded his withdrawal from Iraq by 15 March.
=== Iranian military preparations === In Iran, severe officer purges, including numerous executions ordered by Sadegh Khalkhali, the new Revolutionary Court judge, and shortages of spare parts for Iran's American and British-made equipment had crippled Iran's once-mighty military. Between February and September 1979, Iran's government executed 85 senior generals and forced many other generals into early retirement. By September 1980, some 12,000 officers had been purged from all levels from the army. This reduced the Iranian military's operational capacities. On the eve of the revolution in 1978, international experts in military science had deemed Iran's armed forces the world's fifth most powerful. However, by the eve of war with Iraq, the recently formidable Iranian army was in many crucial ways a shell of its former self, having been badly weakened by losses in experienced personnel. The desertion rate had reached 60%, the officer corps was devastated and its most highly skilled soldiers and aviators had been exiled, imprisoned, or executed. When the invasion occurred, many pilots and officers were released from prison, or had their executions commuted to combat the Iraqis. Throughout the war, Iran never managed to fully recover from this flight of human capital. Many junior officers were promoted to generals, resulting in the army being more integrated as a part of the regime by the war's end. Meanwhile, a new paramilitary organisation gained prominence in Iran, the Islamic Revolutionary Guard Corps (IRGC). Created to protect the new regime and serve as a counterbalance to the army, the IRGC had been trained to act only as a militia and struggled to adapt as needed following the Iraqi invasion, initially refusing to fight alongside the regular army, resulting in many defeats. It was not until 1982 that the two groups began carrying out combined operations. The Basij paramilitary was founded in response to the invasion. They were poorly armed, and had members as young as 12 and as old as 70. Subordinate to the Revolutionary Guard, they made up most of the manpower that was used in the Guard's attacks. Despite neglect by the new regime, at the war's outset, Iran still had at least 1,000 tanks and several hundred functional aircraft, and could cannibalise equipment to procure spare parts. Continuous sanctions greatly limited Iran from acquiring many additional heavy weapons, including tanks and aircraft.
Iraqi military preparations
In addition, the area around the Shatt al-Arab posed no obstacle for Iraqi river-crossing equipment. Iraq correctly deduced that Iran's defences at the crossing points around the Karkheh and Karoun Rivers were undermanned and that the rivers could be easily crossed. Iraqi intelligence was also informed that the Iranian forces in Khuzestan province, which consisted of two divisions prior to the revolution, now only consisted of several ill-equipped and under-strength battalions with only a handful of operational company-sized tank units. The only qualms the Iraqis had were over the Iran Air Force. Despite the purge of several key pilots and commanders, as well as the lack of spare parts, the air force showed its power during local uprisings and rebellions. They were also active after the failed U.S. attempt to rescue its hostages, Operation Eagle Claw. Based on these observations, Iraq's leaders decided to carry out a surprise airstrike against the Iranian air force's infrastructure prior to the main invasion.
=== Khuzestan === It is believed that Iraq sought to either annex, or establish suzerainty over, Iran's Khuzestan province, but Saddam Hussein publicly denied this in November 1980.
Border conflicts leading up to the war
On 10 September 1980, Iraq forcibly reclaimed territories in Zain al-Qaws and Saif Saad that it had been promised under the terms of the 1975 Algiers Agreement but that Iran had never handed over, leading to both Iran and Iraq voiding the treaty, on 14 and 17 September, respectively. As a result, the only outstanding border dispute between Iran and Iraq at the time of the Iraqi invasion of 22 September was the question of whether Iranian ships would fly Iraqi flags and pay Iraq navigation fees for a stretch of the Shatt al-Arab spanning several miles.
Course of the war
1980: Iraqi invasion
Iraq launched a full-scale invasion of Iran on 22 September 1980. The Iraqi Air Force launched surprise air strikes on ten Iranian airfields with the objective of destroying the Iranian Air Force. The attack failed to cripple the Iranian Air Force: while it damaged some of Iran's airbase infrastructure, it did not destroy a significant number of aircraft. The Iraqi Air Force was only able to strike in depth with a few aircraft, and Iran had built hardened aircraft shelters where most of its combat aircraft were stored. The next day, Iraq launched a ground invasion, mounting three simultaneous attacks along a 644 km (400 mi) front. Saddam hoped an attack on Iran would lead to the new government's downfall, or at least end Iran's calls for his overthrow. Four Iraqi divisions were sent to Khuzestan near the border's southern end, to cut off the Shatt al-Arab from the rest of Iran and to establish a territorial security zone. Two other divisions invaded across the border's north and center to prevent an Iranian counter-attack. Two of the four Iraqi divisions, one mechanised and one armoured, operated near the southern end and besieged the strategically important port cities of Abadan and Khorramshahr. The two armoured divisions secured the territory bounded by the cities of Khorramshahr, Ahvaz, Susangerd, and Musian. On the central front, the Iraqis occupied Mehran, advanced towards the Zagros Mountains, and were able to block the traditional Tehran–Baghdad invasion route by securing territory forward of Qasr-e Shirin, Iran. On the northern front, the Iraqis attempted to establish a strong defensive position opposite Suleimaniya to protect the Iraqi Kirkuk oil complex. Iraqi hopes of an uprising by the Arabs of Khuzestan failed to materialise, as most of the Arabs remained loyal to Iran. Patrick Brogan described the Iraqi troops advancing into Iran in 1980 as "badly led and lacking in offensive spirit". The first known chemical weapons attack by Iraq on Iran probably took place during the fighting around Susangerd. Iraqi Minister of Defence Adnan Khayr Allah played a crucial role in rebuilding and modernising the Iraqi military.
Though the Iraqi air invasion surprised the Iranians, their air force retaliated the day after with a large-scale attack against Iraqi air bases and infrastructure in Operation Kaman 99. Groups of fighter jets attacked targets throughout Iraq, such as oil facilities, dams, petrochemical plants, and oil refineries, and included Mosul Airbase, Baghdad, and the Kirkuk oil refinery. Iraq was taken by surprise at the strength of the retaliation, which inflicted heavy losses and economic disruption, but Iraqi air defences also inflicted heavy losses. Iranian Army Aviation's helicopter gunships and fighter-bombers began attacking the advancing Iraqi divisions; they destroyed numerous armoured vehicles and impeded the Iraqi advance, though not completely halting it. Meanwhile, Iraqi air attacks on Iran were repelled by Iran's fighter jets using missiles, which downed a dozen of Iraq's Soviet-built fighters in the first two days of battle. The Iranian regular military, police forces, volunteer Basij, and Revolutionary Guards all conducted their operations separately; thus, the Iraqi invading forces did not face coordinated resistance. However, on 24 September, the Iranian Navy attacked Basra, Iraq, destroying two oil terminals near the port of al-Faw, thus reducing Iraq's ability to export oil. The Iranian ground forces, primarily consisting of the Revolutionary Guard, retreated to the cities, where they set up defences against the invaders. On 30 September, Iran's air force launched Operation Scorch Sword, damaging the nearly-complete Osirak nuclear reactor near Baghdad. By 1 October, Baghdad had been subjected to eight air attacks. In response, Iraq launched aerial strikes against Iranian targets. The mountainous border between Iran and Iraq made a deep ground invasion almost impossible, and air strikes were used instead. The invasion's first waves were a series of air strikes targeted at Iranian airfields. Iraq also attempted to bomb Tehran, Iran's capital, into submission.
First Battle of Khorramshahr
On 22 September, a prolonged battle began in the city of Khorramshahr, eventually leaving around 7,000 dead on each side. The battle began with Iraqi air raids against key points and mechanised divisions advancing on the city in a crescent-like formation. They were slowed by Iranian air attacks and Revolutionary Guard troops. The Iranians flooded the marsh areas around the city, forcing the Iraqis to traverse through narrow strips of land. Iraqi tanks launched attacks with no infantry support, and many tanks were lost to Iranian anti-tank teams. By 30 September, the Iraqis had managed to clear the Iranians from the outskirts of the city. The next day, the Iraqis launched infantry and armoured attacks into the city. The Iraqis were repelled. On 14 October, the Iraqis launched a second offensive. The Iranians initiated a withdrawal from the city. By 24 October, most of the city was captured, and the Iranians evacuated across the Karun River. Some partisans continued fighting until November.
Iraqi advance stalls
Though Khorramshahr was captured, the battle had delayed the Iraqis enough to allow the large-scale deployment of the Iranian military. In November, Saddam ordered his forces to advance towards and besiege Dezful and Ahvaz. However, the Iraqi offensive had been badly damaged by Iranian militias and air power. Iran's air force had destroyed Iraq's army supply depots and fuel supplies, and was strangling Iraq through an aerial siege. Iran's supplies had not been exhausted, despite sanctions, and the military often cannibalised spare parts from other equipment and began searching for parts on the black market. On 28 November, Iran launched Operation Morvarid, an air and sea attack which destroyed 80% of Iraq's navy, and all of the radar sites in the southern portion of the country. When Iraq laid siege to Abadan, it could not blockade the port or prevent seaborne resupply. Iraq's strategic reserves had been depleted, preventing major offensives for years. On 7 December, Saddam announced that Iraq was going on the defensive. By the end of 1980, Iraq had destroyed and captured numerous Iranian tanks.
=== 1981: Stalemate === For the next eight months, both sides were on a defensive footing, with the exception of the Battle of Dezful, as the Iranians needed more time to reorganise their forces after the damage inflicted by the purge of 1979–80. During this period, fighting consisted mainly of artillery duels and raids. Iraq had mobilised 21 divisions for the invasion, while Iran countered with only 13 regular army divisions and one brigade. Seven divisions were deployed to the border. The war bogged down into trench warfare. Due to the power of anti-tank weapons, armoured manoeuvre by the Iraqis was very costly, and they consequently entrenched their tanks into static positions. Iraq also began firing missiles into Dezful and Ahvaz, and used terror bombing to bring the war to the Iranian civilian population. Iran launched dozens of "human wave assaults".
Battle of Dezful
On 5 January 1981, Iran had reorganised its forces enough to launch a large-scale offensive, Operation Nasr. The Iranians launched their major armoured offensive from Dezful in the direction of Susangerd, consisting of tank brigades, and broke through Iraqi lines. However, the Iranian tanks had raced through Iraqi lines with unguarded flanks and without infantry support; as a result, they were cut off by Iraqi tanks. In the ensuing Battle of Dezful, the Iranian armoured divisions were nearly wiped out in one of the biggest tank battles of the war. When the Iranian tanks tried to manoeuvre, they became stuck in the mud of the marshes, and many tanks were abandoned. The Iraqis lost around 45 tanks, and the Iranians, around 100–200. 141 Iranians were killed. The battle had been ordered by Iranian president Abulhassan Banisadr, who was hoping that a victory might shore up his deteriorating political position; the failure hastened his fall. Many of Iran's problems took place because of political infighting between Banisadr, who supported the regular army, and the hardliners, who supported the IRGC. Once he was impeached and the competition ended, the performance of the Iranian military improved. The Islamic Republic government in Iran was further distracted by internal fighting between the regime and the Mujahedin e-Khalq (MEK) on the streets of Iran's major cities in June 1981 and again in September. In 1983, the MEK started an alliance with Iraq following a meeting between MEK leader Massoud Rajavi and Iraqi Deputy Prime minister Tariq Aziz. In 1984, Banisadr left the coalition because of a dispute, and set up a base on the Iranian border.
Attack on H3
The Iraqi Air Force, badly damaged by the Iranians, was moved to the H-3 Air Base in western Iraq, near the Jordanian border and away from Iran. On 3 April 1981, the Iranian Air Force launched a surprise attack on H3, destroying Iraqi combat aircraft. Despite it and other successful air attacks, the Iranian Air Force was forced to cancel its successful 180-day air offensive and abandoned their attempted control of Iraqi airspace. They had been seriously weakened by sanctions and pre-war purges and further damaged by a fresh purge after the impeachment crisis of President Banisadr. The Iranian Air Force could not survive further attrition, and decided to limit their losses, abandoning efforts to control Iraqi airspace. The Iranian air force would henceforth fight on the defensive, trying to deter the Iraqis rather than engaging them. While throughout 1981–1982 the Iraqi air force would remain weak, within the next few years they would rearm and expand again, and begin to regain the strategic initiative.
==== Dispute over use of human wave attacks ==== Various sources claim that because Iran lacked heavy weapons, but had numerous volunteers, they began using human wave attacks against the Iraqis. Typically, an Iranian assault would commence with poorly trained Basij who would launch the primary human wave assaults to swamp the weakest portions of the Iraqi lines en masse (on some occasions even bodily clearing minefields). This would be followed up by the more experienced Revolutionary Guard infantry, who would breach the weakened Iraqi lines, and followed up by the regular army using mechanised forces, who would manoeuvre through the breach and attempt to encircle and defeat the enemy.
Historian Stephen Pelletiere writes that the use of "human wave attacks" is a misconception. Instead, Iranian tactics consisted of using groups of 22-man infantry squads, which moved forward to attack specific objectives. As the squads surged forward to execute their missions, that gave the impression of a "human wave attack". Nevertheless, the idea of "human wave attacks" remained virtually synonymous with any large-scale infantry frontal assault Iran carried out. Large numbers of troops would be used, aimed at overwhelming the Iraqi lines (usually the weakest portion, typically manned by the Iraqi Popular Army), regardless of losses. Former Iraqi general Ra'ad al-Hamdani said the Iranian human wave charges consisted of armed "civilians" who carried most of their necessary equipment themselves into battle and often lacked command and control and logistics. Operations were often carried out during the night and deception operations, infiltrations, and manoeuvres became more common. Infiltrating forces would be reinforced to maintain momentum, all forces would be concentrated onto a newly discovered weak point, and human wave attacks were used to facilitate breakthroughs. Human wave attacks, while killing tens of thousands of troops, caused major Iraqi losses. As the Iraqis would dig in their tanks and infantry into static, entrenched positions, the Iranians would manage to break through the lines and encircle entire divisions. Merely the fact that the Iranian forces used manoeuvre warfare by their light infantry against static Iraqi defenses was often the decisive factor in battle. However, lack of coordination between the Iranian Army and IRGC and shortages of heavy weaponry played a detrimental role, often with most of the infantry not being supported by artillery and armour.
==== Operation Eighth-Imam ==== After the Iraqi offensive stalled in March 1981, there was little change in the front other than Iran retaking the high ground above Susangerd in May. By late 1981, Iran returned to the offensive and launched Operation Samen-ol-A'emeh, ending the Iraqi Siege of Abadan in September. The Iranians used a combined force of regular artillery with small groups of armour, supported by Pasdaran (IRGC) and Basij infantry. In October, after lifting the siege, a large Iranian convoy was ambushed by Iraqi tanks, and during the ensuing battle, Iran lost many armoured vehicles, and withdrew from the previously gained territory.
==== Operation Tariq al-Quds ==== On 29 November 1981, Iran began Operation Tariq al-Quds with three army brigades and seven Revolutionary Guard brigades. The Iraqis failed to properly patrol their occupied areas, and the Iranians constructed a road through the unguarded sand dunes, launching their attack from the Iraqi rear. The town of Bostan was retaken from Iraqi divisions by 7 December. By this time the Iraqi Army was experiencing serious morale problems, compounded by the fact that Operation Tariq al-Quds marked the first use of Iranian "human wave" tactics, where the Revolutionary Guard light infantry repeatedly charged at Iraqi positions, oftentimes without armour or air power. The fall of Bostan exacerbated the Iraqis' logistical problems, forcing them to use a roundabout route from Ahvaz to the south to resupply their troops. 6,000 Iranians and over 2,000 Iraqis were killed in the operation.
1982: Iraqi retreat, Iranian offensive
The Iraqis, realising that the Iranians were planning to attack, decided to preempt them with Operation al-Fawz al-'Azim (Supreme Success) on 19 March. Using a large number of tanks, helicopters, and fighter jets, they attacked the Iranian buildup around the Roghabiyeh pass. Though Saddam and his generals assumed they had succeeded, in reality the Iranian forces remained fully intact. The Iranians had concentrated much of their forces by bringing them directly from the cities and towns throughout Iran via trains, buses, and private cars. The concentration of forces did not resemble a traditional military buildup, and although the Iraqis detected a population buildup near the front, they failed to realise that this was an attacking force. As a result, Saddam's army was unprepared for the Iranian offensives to come.
==== Operation Fath ol-Mobin ==== Iran's next major offensive was Operation Fath ol-Mobin, in March 1982. Iran launched an attack which took the Iraqi forces by surprise: Iranian helicopters landed behind Iraqi lines, silenced their artillery, and captured an Iraqi headquarters. The Revolutionary Guard and regular army followed up by surrounding the Iraqis that had camped close to the Iranian town of Shush. The Iraqis counterattacked, breaking the encirclement and rescuing the surrounded divisions. Iraqi tanks came under attack by Iranian fighter jets. Iraqi forces were driven away from Shush, Dezful and Ahvaz, and the Iranians destroyed numerous Iraqi tanks and armoured vehicles. By this time, most of the Khuzestan province had been recaptured.
Operation Beit ol-Moqaddas
In preparation for Operation Beit ol-Moqaddas, the Iranians had launched numerous air raids against Iraqi air bases, destroying 47 jets (including Iraq's brand new Mirage F-1 fighter jets from France) and gaining air superiority and the ability to monitor Iraqi troop movements. In April, Iran launched the offensive. 70,000 Revolutionary Guard and Basij members struck on several axes—Bostan, Susangerd, the west bank of the Karun River, and Ahvaz. Basij human wave attacks were followed up by the regular army and Revolutionary Guard support. The Iraqi forces retreated, and within a month, Iran had driven out all Iraqi forces from the Susangerd area. The Iranians captured several thousand Iraqi troops and numerous tanks. The Iraqis retreated to the Karun River, with only Khorramshahr and a few outlying areas remaining in their possession. Saddam ordered 70,000 troops to be placed around Khorramshahr. The Iraqis created a hastily constructed defence line around the city and outlying areas, such as metal spikes to discourage airborne commando landings. However, Khorramshahr's only resupply point was across the Shatt al-Arab, and the Iranian air force began bombing the supply bridges to the city, while their artillery zeroed in on the besieged garrison.
Second Battle of Khorramshahr
In the early morning hours of 23 May 1982, the Iranians began the drive towards Khorramshahr across the Karun River. This part of Operation Beit ol-Moqaddas was spearheaded by the 77th Khorasan division with tanks along with the Revolutionary Guard and Basij. The Iranians hit the Iraqis with destructive air strikes and massive artillery barrages, crossed the Karun River, captured bridgeheads, and launched human wave attacks towards the city. Saddam's defensive barricade collapsed; in less than 48 hours of fighting, the city fell and 19,000 Iraqis surrendered to the Iranians. A total of 10,000 Iraqis were killed or wounded in Khorramshahr, while the Iranians suffered 30,000 casualties. During the whole of Operation Beit ol-Moqaddas, 33,000 Iraqi soldiers were captured by the Iranians.
State of Iraqi armed forces
The fighting had battered the Iraqi military: its strength fell from 210,000 to 150,000 troops; over 20,000 Iraqi soldiers were killed and over 30,000 captured; two out of four active armoured divisions and at least three mechanised divisions fell to less than a brigade's strength; and the Iranians had captured over 450 tanks and armoured personnel carriers. The Iraqi Air Force was also left in poor shape: after losing up to 55 aircraft since early December 1981, they had only 100 intact fighter-bombers and interceptors. Only three squadrons of fighter-bombers capable of operations inside Iran. The Iraqi Army Air Corps was in slightly better shape, and could still operate more than 70 helicopters. Despite this, the Iraqis still held 3,000 tanks, while Iran held 1,000. At this point, Saddam believed that his army was too demoralised and damaged to hold onto Khuzestan and major swathes of Iranian territory, and withdrew his remaining forces, redeploying them in defence along the border. However, his troops continued to occupy some key Iranian border areas of Iran, including the disputed territories that prompted his invasion, notably the Shatt al-Arab. In response to their failures against the Iranians in Khorramshahr, Saddam ordered executions of more than a dozen high-ranking officers. This became an increasingly common punishment for those who failed him in battle.
=== Early international response === In April 1982, Iran's ally Syria closed the Kirkuk–Baniyas pipeline that had allowed Iraqi oil to reach tankers on the Mediterranean, reducing the Iraqi budget by $5 billion per month. Journalist Patrick Brogan wrote, "It appeared for a while that Iraq would be strangled economically before it was defeated militarily." Syria's closure of the Kirkuk–Baniyas pipeline left Iraq with the pipeline to Turkey as the only means of exporting oil, along with transporting oil by tanker truck to the port of Aqaba in Jordan. The Turkish pipeline's capacity was insufficient to pay for the war. Saudi Arabia, Kuwait, and the other Gulf states saved Iraq from bankruptcy by providing it with $37–60 billion in loans. Though Iraq had previously been hostile towards other Gulf states, they feared Iranian ideology more than Iraq. Notably, Khomeini had declared monarchies an illegitimate and un-Islamic form of government. Khomeini's statement was widely received as a call to overthrow the Gulf monarchies. Journalists John Bulloch and Harvey Morris wrote:
The virulent Iranian campaign, which at its peak seemed to be making the overthrow of the Saudi regime a war aim on a par with the defeat of Iraq, did have an effect on [Saudi Arabia], but not the one the Iranians wanted: instead of becoming more conciliatory, the Saudis became tougher, more self-confident, and less prone to seek compromise. Saudi Arabia was said to provide Iraq with $1 billion per month starting in mid-1982. Saddam started being aided by the U.S., including massive loans, political influence, and intelligence on Iranian deployments gathered by American spy satellites. Iraq relied heavily on American satellite and radar intelligence to detect and counter Iranian troop movements. With Iranian success on the battlefield, the U.S. increased its support of the Iraqi government, supplying intelligence, economic aid, and dual-use equipment and vehicles, as well as normalising relations (which had been broken during the 1967 Six-Day War). In June 1982, U.S. president Ronald Reagan signed a directive which determined that the U.S. "would do whatever was necessary to prevent Iraq from losing". In 1982, Reagan removed Iraq from the list of countries "supporting terrorism" and sold weapons such as howitzers to Iraq via Jordan. France sold Iraq millions of dollars' worth of weapons. Both the United States and West Germany sold Iraq dual-use pesticides and poisons that would be used to create chemical weapons. Iran lacked funds for comparable purchases. They counted on China, North Korea, Libya, Syria, and Japan for supplying anything from weapons and munitions to logistical and engineering equipment.
