At least 30 people were killed in an attack by gunmen who invaded a village in Nigeria's north central state of Benue, police and witnesses said Monday.The gunmen stormed Iorza village of the state early Sunday, shooting indiscriminately, Austin Ezeani, spokesman of the state police told reporters.He, however, said only four bodies have so far been recovered by security operatives.Local residents who witnessed the attack said at least 30 people, mostly women, children and the aged, were shot dead by the invaders. The village head was among those killed in the attack, John Kaaba, a witness, told Xinhua news agency. He said several others were critically injured before security operatives brought the situation under control. The injured are currently being treated at a state-run health facility near Makurdi, the state capital, he added.It was not clear if the attack was carried out by the Boko Haram, an Islamist terror group in Nigeria, Africa's most populous country. Some residents said it might be a perpetration of local herdsmen fomenting trouble in local communities in central Nigeria.Hundreds of people have been killed in various attacks by local herdsmen in Nigeria's central states of Benue, Nasarawa and Plateau, in the past one year.