The Shatt al-Arab (also called the Arvand Rud in Persian) is a river in the Middle East of some 200 km in length, formed by the confluence of the Euphrates and the Tigris in southern Iraq. At the southern end of the river it constitutes the border between Iraq and Iran down to the mouth of the river as it discharges into the Persian Gulf. Various territorial claims and disputes over navigation rights between these two countries were among the main factors for the Iran-Iraq War that lasted from 1980 to 1988, when the pre-1980 status quo was restored. The city of Basra along this river is Iraq's major port.