Armed men killed four policemen and two soldiers Sunday in separate attacks in Libya, including one in a former bastion of Moamer Kadhafi\'s regime that was toppled last year, security officials said. Assailants using small arms and rocket-propelled-grenades attacked two police stations in the eastern city of Benghazi -- the epicentre of the anti-Kadhafi uprising -- after the arrest of a suspect for his alleged role in several assassinations of police and military officers, an official said. \"Four policemen were killed and three others wounded in the attack by an armed group against the police in Benghazi,\" the official told AFP on condition of anonymity. The attackers were \"radical Islamists,\" he added. He said the attackers were trying to \"free or kill\" a prime suspect held for a series of assassinations that targeted army and police officers in Benghazi in recent months. The suspect was arrested on Saturday. Benghazi was the cradle of the uprising that toppled Kadhadi last year but has increasingly become a focus for jihadist groups, including militants who killed US ambassador Chris Stevens and three other Americans on September 11. Gunmen also killed two army officers on Sunday in the town of Bani Walid which was one of the last strongholds of Kadhafi\'s regime, the military said. Captains Mohamed al-Zarruk and Ahmed al-Haj Mohamed were killed when reinforcements were called in to the oasis town of Bani Walid, 170 kilometres (105 miles) southeast of Tripoli, after interior ministry forces were trapped by gunmen, the army said. \"Members of the (interior ministry-controlled) high security commission were looking for a man accused of murder when armed men surrounded them,\" Bani Walid military commander General Hussein Khalifa told AFP. \"Army units were called to their rescue but they came under fire and two officers were killed.\" Bani Walid has been the scene of repeated clashes between government forces and residents, many of whom rue the overthrow of Kadhafi, who lavished resources on the area during his four-decade rule. In October, former rebel groups stormed the town on defence ministry orders to \"purge\" Kadhafi loyalists. The ensuing clashes left dozens dead and wounded before the authorities took control of the town.