The Syrian Kurdish YPG militia has fully captured Deir al-Zor's eastern countryside from Islamic State with the help of the US-led coalition and Russia, the group says.
The YPG spearheads the Syrian Democratic Forces, an alliance of mostly Kurdish and Arab militias fighting IS with Washington's backing. The SDF offensive in Deir al-Zor province, which borders Iraq, has focused on territory east of the Euphrates river.
On the western bank, the Syrian military has waged its own attack against IS with support from Iran-backed militias and Russia.
The separate assaults advanced from opposite sides of the river, which bisects oil-rich Deir al-Zor, mostly staying out of each other's way. The US-led coalition and the Russian military have held deconfliction meetings, to prevent clashes between planes and troops, though the two offensives have sometimes come into conflict.
The SDF's most powerful component, the YPG, announced on Sunday that it had defeated IS militants on its side "in co-operation with the Arab tribes".
The US-led coalition and Russian forces in Syria provided "air and logistical support, advice and co-ordination on the ground", its statement said. "We hope for an increase in this support and for ensuring the necessary air cover."
A YPG spokesman declared the victory in a village in Deir al-Zor in the presence of a Russian envoy from Moscow's Hmeimim military base in Syria, it said.
