Seven people have been killed in an explosion at a Nigerian camp for people displaced by Islamic extremist attacks, an official said.
Thirteen people were wounded by the explosion in a tent in the Malkohi camp in the outskirts of Yola, capital of Adamawa state in north-east Nigeria, said Saad Bello, the state's National Emergency Management Agency co-ordinator.
The blast was caused by an improvised explosive device left in one of the tents near the camp's central store, police commissioner Gabriel Adaji said.
Suspicion has fallen on the Islamic extremist group Boko Haram, whose uprising has caused the deaths of about 20,000 people since 2009.
More than 1,000 people have been killed since president Muhammadu Buhari was elected in March with a pledge to wipe out the militants. At least 2.1 million others have been driven from their homes by the uprising.
Camps for the internally displaced are spread out in Adamawa, Yobe and Borno states, which have been hardest hit by Boko Haram's uprising.
The group had seized a large area of north-eastern Nigeria, where it declared an Islamic caliphate. A multinational army earlier this year drove the insurgents out of towns and villages but suicide bombings and attacks on villages continue.