An explosion has taken place at a bus station in Damaturu in northeastern Nigeria, killing seven people and injuring 31, witnesses and the local hospital said.
"A girl aged about 12 detonated an explosive under her clothes as she approached the station's perimeter fence," said witness Danbaba Nguru on Saturday.
The head of the local Sani Abacha hospital, doctor Garba Fika, said six bodies and 32 injured had arrived there with one person dying after being admitted.
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The Damaturu bus station has been repeatedly targeted in a string of attacks.
"I was in the station when I saw the young girl arrive," said bus driver Musbahu Lawan.
"I think she noticed the guards checking people at the gates and she decided to detonate the explosives in the middle of the crowd outside the gates."
Nguru added: "The road leading to the gates is always full of small traders... I was lucky not to have been hit."
No claim of responsibility for the attack has been made but Islamist group Boko Haram has frequently used young girls to carry out suicide attacks.