American and Kurdish commandos raided an Islamic State prison compound in northern Iraq, freeing at least 70 Kurdish captives and leaving one U.S. service member dead, sources said Thursday.

It marks the first time a U.S. military member has been killed in a combat situation in Iraq since the United States began attacks against the Islamic State last year.

The operation took place near the northern Iraqi town of Hawija, said individuals familiar with the mission, who spoke on condition of anonymity to discuss an operation whose details have not yet been made public.

At least a dozen Islamic State fighters were believed killed in the raid, the sources said.

The Hawija area has been struck by U.S.-led warplanes seeking to weaken the Islamic State hold on parts of Iraq and Syria.

Western-allied Kurdish fighters also have battled the Islamic State.

Other media reports said some Islamic State militants were captured, but details remained unclear.

There was no immediate official announcement from U.S. officials, but a statement was expected later Thursday.