On Thursday, the Syrian Observatory for Human Rights, a well-sourced monitoring group based in Britain, said that the Islamic State had abandoned its last urban stronghold, Boukamal (or Abu Kamal), following a siege by forces loyal to Syrian President Bashar al-Assad. Pro-Assad forces, including Iranian-backed militias, had entered Boukamal on Wednesday and met some resistance from ISIS remnants. With its ouster from Boukamal, a strategic town on the Iraqi border, ISIS has been relegated to small towns and villages along the Iraq border and in the Syrian desert.
While Syrian government forces and their allies have been attacking ISIS in eastern and central parts of Syria, the U.S.-backed Syrian Democratic Forces (SDF), an alliance of Kurds and Arabs, has been routing ISIS in the north and east. The Assad government said it plans to seize the territory won by the SDF, including former ISIS capital Raqqa and oil-rich territory near the Euphrates River. The SDF-held areas are setting up an autonomous government. Meanwhile, ISIS has been conducting guerrilla strikes from its rural outposts, and still has territory in Libya and elsewhere.