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 declaring the treaty null and void, on 14 September 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 river spanning several miles.