Mosul, Iraq: According to security sources, on Sunday, three policemen were killed in a suicide attack south of Mosul, the northern Iraqi city where Islamic State is controlling a U.S.-backed offensive. A group of about 10 assailants, including four suicide bombers, had tried to percolate a Federal Police helicopter base in Al-Areej, a police captain told Reuters. Three policemen and three of the muggers were killed in the attack, he said. Police gave chase but the attacker managed to escape, he said. Islamic State is now beleaguered in the northwestern part of Mosul, an area that includes the Old City. Its Grand al-Nuri Mosque is where the group's leader, Abu Bakr al-Baghdadi, asserted a "caliphate" over parts of Iraq and Syria in mid-2014.