Gunmen have killed 12 people in an attack on a village in a region of central Nigeria known for bloody clashes between cattle herders and farmers, police said on Thursday. Unknown armed assailants "suspected to be herdsmen" attacked the residents of Kulben village in Plateau state on Wednesday night, the regional police said in a statement. The raid left 12 dead and one person seriously wounded, the authorities said. Local people said 19 people had died. Plateau state is part of Nigeria's so-called middle-belt that divides the mainly-Muslim north from the predominantly Christian south.Deadly clashes between nomadic Fulani herders and farmers over land, grazing and water have plagued the area for years.Aid group Mercy Corps said in May last year that violence between farmers and pastoralists in Nigeria had "contributed to more than 7,000 deaths in the past five years".Attacks in remote areas often go unreported but the authorities in Plateau state insist the bloodshed has decreased following reconciliation efforts between the communities.