A girl suicide bomber, thought to be just 10 years old, blew herself up in a crowded market in northern Nigeria, killing at least 19 people.
The market in Maiduguri, the capital of Borno state, was packed with shoppers and traders when the attack happened at around 12.40pm local time on Saturday.
Civilian vigilante Ashiru Mustapha said the blast happened as the girl was being searched at the entrance to the market.
"The girl was about 10 years old and I doubt if she actually knew what was strapped to her body," he told the AFP news agency.
Several hours later, a suspicious vehicle that had been stopped at a checkpoint outside the city of Potiskum, in neighbouring Yobe, exploded as its driver was taken in by police for questioning.
No group has claimed responsibility for the two blasts, but Boko Haram often carries out attacks in the area and has increasingly used women and young girls as human bombs in their campaign for a hardline Islamic state.
The latest bombings come a week after a major Boko Haram attack on the fishing town of Baga in Borno.
The town and at least 16 nearby settlements were burned to the ground. Amnesty International says up to 2,000 people, mostly women and children, may have been massacred.
Boko Haram launched its first female suicide attack in June last year in the northern state of Gombe and there have been a spate of bombings since.
In July, a 10-year-old girl was found in Katsina state wearing a suicide vest, prompting fears that young girls were being forced into becoming suicide bombers rather than through ideological motivation.
Forced conscription of young men and boys by Boko Haram has been well-documented.
The Islamist militant group is now said to be in control of all three borders of Borno state with Niger, Chad and Cameroon, as well as dozens of towns and villages in Borno, Yobe and Adamawa.