A suicide bomber killed 11 people on Wednesday in an attack on a mosque in northeast Nigeria, the epicentre of the conflict with Islamist insurgency Boko Haram, military officials and an aid worker said.
The bomber hit the mosque in the town of Gamboru in Borno state, near Nigeria's border with Cameroon, during dawn prayers, said Ali Mustapha, an aid worker.
"I was on my way to dawn prayer, then I heard the sound of a loud bomb explosion inside the mosque," Mustapha told Reuters.
"The mosque was destroyed and burnt," he said. "After some hours, when we came to evacuation of the people, we saw 11 corpses, with the suicide bomber making (the total number of dead) 12."
Pictures of the aftermath of the blast showed the bodies of the dead uncovered and lined up on the ground. A building had been reduced to rubble, with only a few sections of wall left standing.
Nobody claimed responsibility for the attack, but it bears the hallmarks of Boko Haram, a jihadist group which frequently uses suicide bombers, often women and girls, to attack crowded public spaces such as mosques and markets.
Despite repeated government and military assertions that the insurgency has been defeated, Boko Haram continues to carry out lethal attacks on the military and civilians.
Last week four civilians were killed in an attack by suspected Boko Haram militants on Maiduguri, the Nigerian city at the centre of the conflict with the Islamists.
In November a suicide bomber killed at least 50 people in an attack on a mosque, in one of the deadliest bombings of recent years.