Boko Haram has been blamed for a spate of attacks in recent weeks, such as this one on a school in Buni Yadi, Yobe State
Two explosions targeting a busy market in the town of Maiduguri in northeast Nigeria have left several people dead.
Eyewitnesses told the Reuters news agency that that 10 people had been killed and that more were feared trapped under rubble.
Maiduguri is the headquarters of a military force fighting against the Boko Haram Islamist group, which has stepped up its attacks in the area.
No group has yet claimed responsibility for the attack.
Eyewitnesses said that the attack was carried out using a car bomb at a crowded market near the airport.
The second bomb went off two minutes later as neighbours arrived to help the victims.
Eyewitnesses described seeing people blown apart and body parts in the street.
In a separate incident, eyewitnesses told the BBC that 20 people were killed in a government airstrike in the village of Daglun on Friday.
Military jets have been bombing the area for weeks as part of a campaign against the Boko Haram group.
An army spokesman told the Associated Press that he was unaware of the death of any civilians in an airstrike.
President Jonathan declared a state of emergency in Adamawa, Yobe and Borno states last year in an attempt to curb the insurgency.
His critics say the state of emergency has been ineffective, with Boko Haram stepping up attacks in the region.
The group is thought to have killed at least 37 people during an assault on a town and nearby villages Adamawa state on Thursday.
It was also blamed for killing at least 29 people in an attack on Monday night on a rural boarding school in Yobe state.
Boko Haram has been conducting a four-year campaign of violence to push for Islamic rule in northern Nigeria.
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