Nigerian officials say a suicide bomb blast at a crowded market in northeastern Nigeria that killed at least 16 people was set off by a girl believed to be about 10 years old.
A police officer told Reuters news agency that "explosive devices were wrapped around her body."
A witness to the explosion in Maiduguri Saturday told the French news agency the blast happened as the girl was being searched at the entrance to the market. He said he doubted if "she knew what was strapped to her body," adding that he was "pretty sure" the bomb was remotely controlled. About 20 people were wounded by the blast.
There was no immediate claim of responsibility, but Maiduguri - the capital of Borno state - lies in the heartland of an insurgency by the Sunni Muslim militant group Boko Haram.
In Potiskum, another target of Boko Haram, a police official told a reporter a car explosion that killed two people was a suicide attack.
The latest attacks came a week after Boko Haram militants seized control of the town of Baga in northern Borno state after intense gun battles with Nigerian soldiers.
Officials say the militants have since burned down much of Baga and surrounding villages, prompting thousands of people to flee to Maiduguri or to islands in Lake Chad.
Estimates of the number of civilians killed in the past week range from several hundred up to 2,000. Boko Haram has been blamed for violence that killed thousands of people during the past five years.
Meanwhile, candidates are beginning to campaign for Nigeria's presidential and parliamentary elections in February.
President Goodluck Jonathan, who is running for re-election, has come under strong criticism for failing to stop Boko Haram. The group, whose name means "Western education is a sin," has seized large parts of Borno state for what its leader calls an Islamic caliphate.