POTISKUM, Nigeria — Islamic militants attacked a boarding school before dawn on Saturday, dousing a dormitory in fuel and lighting it ablaze as students slept, survivors said. At least 30 people were killed in the deadliest attack yet on schools in Nigeria’s embattled northeast.

Survivors at the Potiskum General Hospital said gunmen attacked Government Secondary School in the village of Mamudo, three miles from the town of Potiskum, around 3 a.m. on Saturday.

The authorities blamed Boko Haram, a radical group whose name means “Western education is sacrilege.”

The gunmen killed 29 students and an English teacher, Mohammed Musa, who was shot in the chest, according to another teacher, Ibrahim Abdu.