Rebels from Nigeria's Movement for the Emancipation of the Niger Delta (MEND) have declared a 60-day ceasefire following the government's release of the group's leader, Henry Okah.

The administration granted Mr Okah an amnesty after he agreed to lay down his weapons. However, in an interview after his release, Mr Okah said the war is not over and that he only accepted the amnesty because he urgently needs medical treatment that is not available in prison.

MEND rebels, along with other militant groups, have been attacking oil installations in the Niger Delta as part of a campaign to force a more equitable distribution of the wealth generated by the vast oil and gas resources in the region.