On 17 September the Jordanian army surrounded cities that had a PLO presence, including Amman and Irbid, and began shelling the fedayeen, who had established themselves in Palestinian refugee camps. The next day, a force from Syria with PLO markings started advancing towards Irbid, which the fedayeen declared a "liberated" city. On 22 September, the Syrians withdrew after the Jordanian army launched an air-ground offensive that inflicted heavy Syrian losses, and after Israeli Air Force jets flew over Syrian units in a symbolic show of support of Hussein, but did not engage. An agreement brokered by Egyptian President Nasser between Arafat and Hussein led to an end to the fighting on 27 September. Nasser died the following day of a heart attack. On 13 October Hussein signed an agreement with Arafat to regulate the fedayeen's presence, but the Jordanian army attacked again in January 1971. The fedayeen were driven out of Jordanian cities one by one until 2,000 fedayeen surrendered after being encircled in a forest near Ajloun on 17 July, marking the end of the conflict.