A girl thought to be as young as seven has killed herself and another seven people in a bomb attack at a market in Potiskum, a town in Yobe State.
Nineteen people injured in the blast were taken to hospital, a local vigilante leader, Buba Lawan, told AFP.
No group has claimed responsibility for the attack, but suspicion is likely to fall on terror group Boko Haram, which often carries out its bloody campaign in Yobe and other states in northern Nigeria.
The group is renowned for using children in its attacks, particularly after it kidnapped some 220 schoolgirls in Borno state last April.
Shortly after the mass abduction, reports emerged that female suicide bombers had increased throughout northern Nigeria.
In February, a female suicide bomber detonated a device at a bus station in the city of Damaturu, capital of Yobe State, killing at least 10 people.
The blast in Potiskum is only the latest of a series of attacks carried out by the insurgents while Nigerian President Goodluck Jonathan postponed presidential elections by six weeks amid security concerns.
Some have criticised the delay, arguing that Jonathan is trying to gain more votes and defeat the opposition.
Others hope that the six week-delay could allow African Union forces - comprising troops from Nigeria, Chad, Benin, Cameroon and Niger - to combat Boko Haram and recapture territories occupied by the insurgents.