Islamic extremists have killed 29 students and one teacher in an attack on a boarding school in north-east Nigeria.

Survivors being treated for burn and gunshots wounds say some students were burned alive in the pre-dawn attack on Government secondary school in Mamudo town, Yobe state, on Saturday.

Crying over the bodies of his two boys, farmer Malam Abdullahi swore he would withdraw his three remaining sons from a nearby school. He said there was no protection for students despite the deployment of thousands of troops since the government declared a state of emergency in three north-eastern states in mid-May due to attacks by the terrorist group Boko Haram.

Dozens of schools have been torched and scores of students killed among more than 1,600 victims slain by extremists since 2010.