Eleven civilians were killed in four separate air strikes by the U.S.-led coalition fighting Islamic State in Iraq and Syria between Oct. 25 and Dec. 9, the U.S. military said on Thursday.

“Although the Coalition takes extraordinary efforts to strike military targets in a manner that minimizes the risk to civilian casualties, in some incidents casualties are unavoidable,” the military said in a statement.

In an incident on Dec. 7, near Raqqa, Syria, the military said seven civilians were killed in an air strike on a building where Islamic State fighters were present.