BEIRUT (AP) — Syria's main Kurdish forces say it has successfully cleared areas east of the Euphrates river of Islamic State militants.

Noureddine Mahmoud, spokesman for the People's Defense Units, known as the YPG, and the backbone of the U.S.-backed Syrian Democratic Forces, praised at a press conference Sunday U.S. and Russian support for forces operating in the eastern Deir el-Zour province. He said he hoped for more coordination with the two international powers to protect liberated areas. Mahmoud's comments come a day after the U.S. defense secretary said Washington will stop arming the YPG.

Russia is the main backer of Syrian government forces battling IS on the western side of the river. Russia and the U.S. have been in contact to prevent clashes between them.