Damascus, May 18 (RHC)-- A U.S. raid in eastern Syria has killed 32 members of the ISIL terrorist group, including four of its leaders, sources say. The operation was launched by U.S. Special Operations forces in Deir ez-Zor province, without coordination with the Syrian government.

U.S. officials said on Saturday "about a dozen" people were killed in the operation, but a Britain-based monitoring group revealed on Sunday that at least 32 ISIL terrorists were killed.

U.S. troops also reportedly arrested Abu Sayaf's wife who allegedly played a key role in ISIL activities. According to an anonymous source, the woman was taken to an unknown detention center in Iraq.

The U.S. forces slipped into Syria from Iraq upon direct orders from U.S. President Barack Obama. Syria said they did so without notifying Damascus. An American military with knowledge of details of the raid said a team of Delta Force commandos entered Syria from Iraq under cover of darkness aboard Black Hawk helicopters and V-22 Osprey aircraft, which take off and land like helicopters and cruise like planes.

Abu Sayyaf and his men put up stiff resistance and even fired at their aircraft, causing bullet-hole damage to Osprey, said the official, who spoke on condition of anonymity because he was not authorized to discuss the raid details.