Gunmen killed at least 18 people in Nigeria’s northern Benue state in a weekend attack, residents and local officials said, triggering a march by angry locals who blocked roads in protest at the violence.Benue has been the frequent scene of clashes involving farming communities and cattle herders, as well as attacks by armed groups, in conflicts often driven by competition over land and resources.Benue police spokesperson Udeme Edet gave a lower death toll for the attack, which took place early on Sunday, saying eight people had died and five were wounded.The incident occurred in the Otukpo-Nobi community of the Otukpo Local Government Area, where residents said armed men, suspected by locals to be Fulani herders, opened fire between about 3:30 a.m. and 4:30 a.m.Local government chair Maxwell Ogiri linked the violence to the killing of the chair of the herders’ association two weeks ago.No group immediately claimed responsibility for the attack.Women and youths from the affected community later marched through the town of Otukpo to protest.