BEIRUT (AP) — U.S.-backed Syrian fighters have cut the main road between the northern Syrian city of Raqqa, which is controlled by the Islamic State group, and the eastern city of Deir el-Zour, which is partially controlled by IS.

The Britain-based Syrian Observatory for Human Rights says fighters from the Kurdish-led Syria Democratic Forces cut the road linking the two cities in the area of Jazra near Raqqa, the de facto capital of the IS self-declared caliphate.

SDF said in a statement Monday that its fighters captured seven area villages, enabling them to blockade the road.

SDF fighters have been on the offensive under the cover of airstrikes by the U.S.-led coalition since November as part of operation Euphrates Wrath, which aims to surround and capture Raqqa.