Nigerian security forces have raided a suspected bomb-making factory, killing at least nine alleged Islamist militants, officials say.The raid, in the Okene district of Kogi state, came after the authorities discovered the facility they believe was run by the Boko Haram sect.Two members of the security forces were killed in the firefight.Boko Haram has launched a series of deadly attacks across northern Nigeria since 2009.Sunday's raid took place much further south, in Kogi state, and involved helicopters and dozens of security personnel, according to local media."There were some skirmishes between some hoodlums and the military," Jacob Edi, a spokesman for the state governor, told AFP news agency.Officials said they believed the hideout belonged to Boko Haram, and described the nine people killed as "terrorists".Boko Haram's name means "Western education is sinful" in the Hausa language, and their stated aim is to overthrow the national government and install an extreme form of Islamic law.Their attacks, mostly in the north of the country, have killed hundreds of civilians, both Muslim and Christian.