(Adds background) BAGHDAD, May 8 (Reuters) - A car bomb exploded in a public square in the Iraqi Shi'ite city of Kufa on Tuesday and there were some casualties, police said. Car bombs are rare in Kufa, which is south of Baghdad and near the holy Shi'ite city of Najaf. No more information was immediately available. A string of car bombs blamed on Sunni Islamist al Qaeda has killed hundreds in recent weeks despite a U.S.-backed security crackdown in Baghdad and outlying areas. The crackdown is seen as a last-ditch attempt to stop Iraq from sliding into all-out civil war between majority Shi'ites and once-dominant Sunni Arabs. (Writing by Ibon Villelabeitia, editing by Dean Yates)
