Militants have killed an estimated 40 pupils in a pre-dawn attack on a Nigerian school, setting ablaze a locked hostel then shooting and slitting the throats of those who escaped through windows. Survivors said some of the victims, aged 11 to 18, had been burned alive by the attackers,thought to be members of Islamist extremist group Boko Haram, which is opposed to "western-style" education. Teachers who fled through the bush said around 40 pupils died in the assault, which began at around 2am on Tuesday in the town of Buni Yadi in the north-eastern state of Yobe. Soldiers were still gathering corpses so could not give an exact number of dead, a military spokesman said. The school is about 45 miles south of Damaturu, Yobe's capital. Communications in the area are limited because extremists last year destroyed the local mobile-phone tower. Adamu Garba, a teacher, said the attackers first set ablaze the school's administrative block, then moved to the hostels...