WASHINGTON, Dec 22 (Reuters) - The U.S.-led coalition conducted 12 air strikes against Islamic State militants in Syria on Monday and 10 strikes Iraq, the U.S. military said in a statement. In Iraq, the strikes hit near the strategic northern Iraqi town of Sinjar as well as near Asad, Tal Afar, Ramdi, Mosul and Falluja, the Combined Joint Task Force said.