A video released Sunday by a rebel faction fighting within the ranks of the Free Syrian Army documents ISIS forces withdrawing from the strategic town of al-Dumayr near Damascus under heavy protection from Bashar Assad's forces.The video shows ISIS forces leaving the town in a mass convoy of vehicles, while several Syrian Arab Army helicopters fly above them to assure their safe withdrawal.ISIS withdrew from al-Dumayr on Wednesday, after concluding a deal with the Syrian regime. According to this agreement, the regime forces, that were besieging the town, would allow the organization's fighters, especially the wounded ones, to leave al-Dumayr, in exchange for ISIS surrendering the heavy ammunition it seized in the town.According to the Syrian media, ISIS withdrew from the town accompanied by ambulances of the Syrian Red Cross that carried injured ISIS fighters. The Syrian rebel organization denounced the developments described in the video and claimed that it is additional evidence of the cooperation between the Syrian regime and ISIS. Such allegations were also spread on Thursday, when an ISIS suicide bomber attacked Kurdish forces in the disputed town of Qamishli, in northern Syria, amid lethal fighting that took place between the Kurdish forces and Assad forces.Located 40 kilometers north-east of Syria, al-Dumayr witnessed a wide military offensive by ISIS forces in the beginning of April, in a bid to liberate the town from Assad's forces.During its offensive, ISIS abducted 300 cement workers and contractors from their workplace in the town. On April 10, the terrorist group announced that it had freed all but four of the workers, whom it killed for belonging to the minority Druse sect.