Iraqi troops clashed with gunmen from a messianic Shiite cult Friday in southern Iraq, leaving at least six people killed and nine wounded, police said. The battles in Basra and Nasiriyah began after members of the Soldiers of Heaven group, called the Jund al-Samaa in Arabic, attacked police and worshippers preparing for Ashoura, the holiest day on the Shiite calendar. The cult, which is considered heretical by mainstream Shiite clerics, was the target of a bloody battle outside Najaf nearly a year ago after Iraqi authorities raided the group's lands to foil an alleged plot to slaughter pilgrims and leading clerics during Ashoura. The violence began after noon with a mortar attack targeting police in Nasiriyah, a predominantly Shiite city some 320 kilometers southeast of Baghdad, followed by fierce clashes between gunmen and police. Police said the attackers were carrying yellow flags indicating they belonged to the Soldiers of Heaven.