Security forces on Wednesday attacked the camp of a leading Nigerian oil-region gang member whose fighters were implicated by police in a recent gunbattle that left more than a dozen people dead, according to AP. The military and police attacked a base for fighters linked to Soboma George early Wednesday and arrested unspecified militants, said the military spokesman, Sagir Musa. Gunfire continued into daylight hours in the city of Port Harcourt, the oil-region's largest city, residents said. Musa said George wasn't among those arrested, but refused to comment on whether he had been killed or wounded in the operation. There was no word on any casualties Police say forces linked to George were involved in the Port Harcourt battle last week with fighters loyal to another gang member, Ateke Tom, although Tom denied that. At least 15 people died in days of sporadic street fights that ended over the weekend. Local media reported that the gang members were fighting for turf and rights to the lucrative trade in crude oil stolen from pipelines and sold on the black market. Both Tom and George are wanted by authorities. Neither go to great lengths to conceal their movements, even traveling on occasion in large convoys of vehicles. Musa said security forces intended to crack down. The two gangs are believed to be primarily motivated by criminal motives. But many fighters in the southern oil region move between criminal and militant acts, whose stated aims are dislodging more federally controlled funds for the region where the oil is pumped in Africa's biggest producer. Lawlessness across the southern region has flourished since militants intensified their activity in late 2005. Kidnappings and gunfights are now common.