Residents say a suicide bomber entered a mosque in a northern Nigerian town and detonated his explosives, killing at least 10 people during early morning prayers.
Bukar Jibril, a youth volunteer in Gamboru Ngala town, says nine bodies were found immediately after the blast and two other people died later, including the bomber.
Two other residents confirmed Wednesday's attack in Borno state.
The Borno state government on Tuesday tightened a curfew and increased security checks around its capital, Maiduguri, after a resurgence of violence in the city where Islamic extremist group Boko Haram was formed.
Boko Haram's eight-year insurgency has killed tens of thousands of people.
Nigerian President Muhammadu Buhari in his New Year's address again claimed that Boko Haram had been largely defeated.