A suspected female suicide bomber blew herself up in a market in the town of Biu in Nigeria's northeast Borno state on Thursday, witnesses and a community leader said.
"Many" people were feared dead and scores wounded, community leader Ali Mai Biu said. A death toll could not immediately be confirmed.
Borno state is the heartland of Islamist sect Boko Haram, which has been waging an insurgency for more than five years and wants to establish a caliphate.