Syrian government and allied forces have taken the eastern town of al-Mayadeen from Islamic State, a Syrian military source said on Saturday, further weakening the militants’ diminishing presence in Syria, Reuters reported.

Al-Mayadeen, near the Iraqi border in Deir al Zor province, had become a major base for Islamic State militants as they were being driven out of their de facto Syrian capital in Raqqa city by a U.S.-backed offensive.

Over the past few months many of the individuals which the U.S.-led coalition against Islamic State has targeted have come from al-Mayadeen, coalition spokesman Ryan Dillon told Reuters.

The Syrian government campaign to take al-Mayadeen has been supported by heavy Russian air strikes. The U.S.-led coalition has also previously struck in the vicinity of the town.

Al-Mayadeen lies south of the provincial capital Deir al-Zor city, where Syrian and allied forces are also trying to oust the militants from a small pocket they still control.

The Syrian military source said the jihadists in al-Mayadeen had suffered a “collapse” in their ranks.