U.S. special forces have killed a senior Islamic State (IS) member and captured his wife in a rare raid in eastern Syria, the Pentagon said Saturday, May 16, according to BBC News.

Abu Sayyaf helped direct oil, gas and financial operations for IS, as well as holding a military role, the U.S. Department of Defense statement said.

He was killed when he engaged U.S. forces, the statement said.

The operation in al-Amr was authorized by President Barack Obama and was carried out by forces based in Iraq.

None of the U.S. troops involved in the overnight operation were killed or injured, the White House said.

It said that Abu Sayyaf's wife, Umm Sayyaf, is suspected of being an IS member and of being complicit in the enslavement of a young Yazidi woman who was rescued in the raid.

Umm Sayyaf has been taken into military detention in Iraq.

Syrian state media earlier reported that government forces had killed at least 40 IS fighters, including IS's "oil minister", in an attack on the country's largest oil field in Deir ez-Zor.

Oil and gas have been an important source of revenue for IS, which took control of large swathes of territory in Syria and Iraq last year.

On Wednesday, the Iraqi government said IS's second-in-command had been killed in a U.S.-led coalition air strike in northern Iraq - a claim that has not been confirmed by the U.S.

Meanwhile, Iraqi forces have been battling IS militants in the city of Ramadi, where they seized key buildings on Friday.

In Syria, government forces have been trying to drive back IS fighters from the desert World Heritage Site of Palmyra.

Also this week, IS released an audio message that it said was from its leader, Abu Bakr al-Baghdadi. If verified, it would be his first such message for several months.