Nigerian police investigate school suicide attack

Dozens of students have been killed by a suicide bomber at a school assembly in the north-eastern Nigerian town of Potiskum.

The explosion at a boys' school in the town is believed to have been carried out by the Islamist militant group Boko Haram.

The group has targeted schools during a deadly five-year insurgency aimed at establishing an Islamic state.

Nigeria's police spokesman Emmanuel Ojukwu told the BBC security forces were working "round the clock" to "restore normalcy" to Nigeria.

It is waging a sustained campaign to prevent children from going to school. It believes girls should not attend school and boys should only receive an Islamic education.