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

Survivors are being treated for burn and gunshots wounds following the attack on Government Secondary School in Mamudo town in Yobe state.

The Nigerian government declared a state of emergency mid-May in three northeastern states.

Dozens of schools have been torched and an unknown number of students are among more than 1,600 victims killed by extremists since 2010.