Gunmen suspected to belong to a radical Islamist sect attacked a village in northeast Nigeria, tying up men, women and children before slitting their throats, killing at least 15 in the troubled region's latest attack, witnesses said Saturday.The assault happened early Friday morning in the village of Musari on the outskirts of Maiduguri, the city where the sect known as Boko Haram first launched its guerrilla campaign of shootings and car bombings against Nigeria's weak central government. The gunmen shouted religious slogans and later ordered those there to be gathered up into a group, said Mshelia Inusa, a primary school teacher in the village."We heard some people chanting, 'God is great, God is great' amid sounds of banging on doors of houses at about 1 a.m.," the teacher said. "A voice was heard ordering people to be slaughtered and also voices of children were heard screaming."Inusa said he and others later saw corpses with their hands tied behind their backs and their throats cut.Later Friday morning, an ambulance arrived at the State Specialists Hospital in Maiduguri, accompanied by a group of military vehicles, a security guard said. Agitated soldiers ordered people away, but the guard said he counted at least 15 bodies being brought into the facility's morgue.The guard spoke on condition of anonymity out of fears of angering either the military or the sect.Lt. Col. Sagir Musa, a military spokesman, later issued a statement saying only five people had been killed in the village during the attack. However, military and police officials routinely downplay casualty figures because they are under increasing pressure from their superiors to minimize the perceived effects of the ongoing attacks by Boko Haram.Boko Haram, which speaks to journalists through conference calls at times of its choosing, could not be immediately reached for comment Saturday. However, the attack mirrored other assaults carried out by the group as it expands its operations outside of cities in the northeast into rural towns and villages, where the security presence remains light and contact with the outside world remains difficult as the sect has destroyed a number of mobile phone towers recently.The sect, whose name means "Western education is sacrilege" in the Hausa language of Nigeria's Muslim north, wants the nation to enact strict Shariah law and release its imprisoned members. Despite a heavy military and police presence, the sect's adherents have continued to launch frequent attacks.More than 780 people have been killed in Boko Haram attacks so far this year, according to an Associated Press count, making 2012 the worst year of violence attributed to the group. Boko Haram also has loose connections with al-Qaida in the Islamic Maghreb and Somalia's al-Shabab, according to Western military officials and diplomats.Suspected Boko Haram gunmen also attacked another village Friday in Adamawa state on its border with neighboring Cameroon. Witnesses said that attack focused on the town of Maiha, where gunmen also shouted praises to God while setting fire to government buildings, a school and a prison. Witnesses said at least two people died in the attack. A police spokesman later confirmed the attack took place, but declined to offer any details.And violence continued around the central Nigerian city of Jos, where ethnic, religious and political rivalries have caused mass killings in recent years. Authorities said at least seven had been killed in recent days around Christian villages in the rural plateau. Police said they were investigating the attacks.