ONITSHA, Nigeria - - Bank robbers armed with assault rifles and high explosives attacked four banks and two police stations in southern Nigeria, in a coordinated strike that left seven people dead, police said on Tuesday.It was the latest in a spate of security lapses in Nigeria in the past two days, after a suicide bombing by suspected Islamists inside a military barracks on Sunday and a jail break in the capital Abuja in the early hours of Monday.The attack took place late on Monday night in the remote town of Auchi, in Edo state. The robbers opened fire and detonated dynamite at several of the targets, police commissioner for Eddo state Hurti Mohammed told Reuters by telephone.They robbed the vault in Access Bank but were unable to get money out of any of the other banks. Seven people, including a bus driver, were killed in the ensuing gun battle with police, he said, adding that the robbers had escaped."They shot sporadically and were able to gain access to the vault of one of the banks ... carting away an unspecified amount of cash," he said. "No policeman was killed."