Explosions and gunfire have been heard in the northern Nigerian city of Gombe.
Reports said the blasts began around the time of evening prayers on Friday.
People were fleeing an area of the city near a prison and police station.
Earlier on Friday, gunmen killed five people were killed at a mosque in Kano, the main city in northern Nigeria.
Police said the gunmen arrived on motorcycles and opened fire at worshippers.
Gombe was targeted by the Boko Haram group in January, when six people were killed in a church in the city.
A state of emergency was declared in parts of the north in late December by President Goodluck Jonathan, after 37 people were killed in a bombing in a Catholic church in Abuja.