An airstrike by the US-led coalition fighting the Islamic State group targeted a mosque in Syria last week because it was determined to be an insurgent command-and-control center, the US said Sunday.

The coalition said in a statement that while the law of war protects mosques, the use of the building as a headquarters by IS caused it to lose that protected status. It said a dozen fighters were killed.

US Army Gen. Joseph Votel, the top American commander for the Middle East, said Sunday that he is very satisfied that commanders went through the proper procedures to determine that the mosque was being used by IS and that it was a legitimate target.

“The determination that was made by the leadership on the ground that this was this mosque was not being used as a mosque,” Votel told reporters traveling with him in Qatar. “These aren’t hastily made decisions.”

Syrian state media and the Britain-based Syrian Observatory for Human Rights said last week that a series of strikes in Sousa near the Iraq border killed and wounded dozens; civilians as well as IS fighters.

The coalition’s statement, focused on the mosque, said monitoring of the building “made us aware” of when only IS fighters were present. It said the strike took place Thursday when it was being used to coordinate attacks on the coalition and on US-backed Syrian Democratic Forces.

Sousa is in the last IS-held pocket in Syria and Syrian Democratic Forces have been on the offensive for weeks trying to clear the area of the extremists.

The statement did not acknowledge or refute the reports of civilian deaths from coalition airstrikes in the area. “We conduct inquiries into all credible allegations of civilian casualties,” it said.

IS fighters recently stormed a settlement for displaced people in the area and kidnapped 130 families. (AP)