BEIRUT (AP):

A United States backed Syrian force says it has launched military operations against the Islamic State (IS) group in eastern Syria, heightening the possibility of conflict with rival, Russian-backed government forces, which are running their own operations in the same area.

The predominantly Kurdish Syrian Democratic Forces announced that its Deir el-Zour Military Council has launched operation "Jazeera Storm" to defeat IS militants in the resource-rich Deir el-Zour province.

Syrian government forces broke an IS siege against the provincial capital, also called Deir el-Zour, last week.

The SDF remain locked in battle with IS militants over the jihadists' de-facto capital city, Raqqa, in north Syria. The US military is providing ground and air support.