Iraq had, since 1970, enjoyed a fluctuating relationship with Syria, sometimes distant and sometimes close enough to contemplate a complete political and economic union.
By 1980, however, the atmosphere was cool. Relations between Iraq and Iran had been tense for some years, with disagreement over their shared border, which runs down the Shatt-al-Arab waterway.
The 1979 Iranian revolution made Iraq more suspicious of Iran’s intentions and in 1980 a full-scale war broke out.
The war – which took place from 1980 to 1988 – was claimed by Iran to have begun with the Iraqi offensive on 21 September 1980, and by Iraq with the Iranian shelling of border posts on 4 September 1980.
Occasioned by a boundary dispute over the Shatt-al-Arab waterway, it fundamentally arose because of Saddam Hussein‘s fear of a weakening of his absolute power base in Iraq by Iran’s encouragement of the Shiite majority in Iraq to rise against the Sunni government.
The course of the war was marked by offensive and counter-offensive, interspersed with extended periods of stalemate. Chemical weapons were used, cities and important oil installations of the area were the targets for bombing raids and rocket attacks, and international shipping came under fire in the Persian Gulf – including, in 1987, the US frigate Stark which was attacked by the Iraqi air force.
Among Arab states, Iran was supported by Libya and Syria, the remainder supporting Iraq. Iran also benefited from secret US arms shipments, the disclosure of which in 1986 led to a considerable scandal in the USA, referred to at the time as ”Irangate”.
The intervention of the USA in 1987 – ostensibly to keep the sea lanes open but seen by Iran as support for Iraq – heightened, rather than reduced, tension in the Gulf, and United Nations attempts to obtain a ceasefire failed.
The war ended in August 1988 after ceasefire talks in Geneva. An estimated 1 million people died in the war.
At the peak of the war, Iran and Iraq were spending $10 billion a year on weapons and 27 countries were supplying both sides.
During the war, 414 ships were hit by missiles, causing 250 deaths. 90,000 of the soldiers that were killed were under the age of 15.
Iraq and Iran finished repatriating more than 5,500 prisoners in early April 1998, according to the International Committee of the Red Cross (ICRC), which supervised the exchange.
Most of the prisoners had been in captivity for over 15 years and the exchange was the biggest repatriation of Iranian and Iraqi POWs since 1990.