on 17 September 1980, Iraq suddenly abrogated the Algiers Protocol following the Iranian revolution. Saddam Hussein claimed that the Islamic Republic of Iran refused to abide by the stipulations of the Algiers Protocol and, therefore, Iraq considered the Protocol null and void. Five days later, the Iraqi army crossed the border.
September 18–19, 1980: the Damascus Accident, occurred in Damascus, Arkansas, where a Titan missile equipped with a nuclear warhead exploded. The accident was caused by a maintenance man who dropped a socket from a socket wrench down an 80-foot (24 m) shaft, puncturing a fuel tank on the rocket. Leaking fuel resulted in a hypergolic fuel explosion, jettisoning the W-53 warhead beyond the launch site.
On 22 September, a prolonged battle began in the city of Khorramshahr, eventually leaving 7,000 dead on each side. Reflecting the bloody nature of the struggle, Iranians came to call Khorramshahr "City of Blood".
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 damage the Iranian Air Force significantly; it damaged some of Iran's airbase infrastructure, but failed to destroy a significant number of aircraft.
On 22 September 1980, when Saddam Hussein launched an invasion of Iran, setting off the Iran–Iraq War (1980–1988), Soleimani joined the battlefield serving as the leader of a military company, consisting of men from Kerman whom he assembled and trained.
The next day, Iraq launched a ground invasion along a front measuring 644 km (400 mi) in three simultaneous attacks. The invasion's purpose, according to Saddam, was to blunt the edge of Khomeini's movement and to thwart his attempts to export his Islamic revolution to Iraq and the Persian Gulf states.
Though the Iraqi air invasion surprised the Iranians, the Iranian air force retaliated the day after with a large-scale attack against Iraqi air bases and infrastructure in Operation Kaman 99. Groups of F-4 Phantom and F-5 Tiger 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.
On 24 September, the Iranian Navy attacked Basra, Iraq, destroying two oil terminals near the Iraqi port Faw, which reduced 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.
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. After heavy house-to-house fighting, the Iraqis were repelled.