From March 1974 to March 1975, Iran and Iraq fought border skirmishes over Iran's support of Iraqi Kurds.[2][5] In 1975, the Iraqis launched an offensive into Iran using tanks, though the Iranians defeated them.[6] Several other attacks took place; however, Iran had the world's fifth most powerful military at the time and easily defeated the Iraqis with its air force. Some 1,000 people died on the course of the 1974-75 clashes in the Shatt al-Arab region.[7] As a result, Iraq decided against continuing the war, choosing instead to make concessions to Tehran to end the Kurdish rebellion.[2][5] In the 1975 Algiers Agreement, Iraq made territorial concessions—including the Shatt al-Arab waterway—in exchange for normalised relations.[2] In return for Iraq recognising that the frontier on the waterway ran along the entire thalweg, Iran ended its support of Iraq's Kurdish guerrillas.[2]