At least three explosions struck a military checkpoint in the northeast Borno town of Biu on Tuesday, witnesses and a security source said.
Witness Auwalu Ibrahim, a local pro-government vigilante, said there were children around the checkpoint when the blasts went off.
The cause was unclear, although the town has been repeatedly attacked by Islamist militant group Boko Haram.
The blasts occurred barely five days after a suicide bomber killed 8 persons and injured over 40 other traders in Biu market.
At least 37 people died in Biu town in Southern Borno state when multiple explosions occurred at a military checkpoint at the entrance of the town, security sources and witnesses have said.
A nurse at Biu general hospital said eight bodies had been brought in from the blast. Six people were receiving treatment for wounds, she said. The military did not respond to a request for comment.
Boko Haram's relentless attacks on military and civilians have killed thousands since the group launched its violent campaign for a breakaway Islamic state in mid-2009.
It has become the main threat to the stability of Nigeria, Africa's biggest economy and leading oil producer, as well as a major threat to the surrounding region. Neighbours Niger, Chad and Cameroon are all engaged in fighting the rebels.
Tens of thousands of people marched through Niger's capital Niamey on Tuesday to support their military following a series of Boko Haram attacks along the Nigeria border.
Nigerian soldiers recaptured two towns on Monday as U.S. and regional troops began war games in neighbouring Chad in a growing international campaign.
Involvement by Nigeria's neighbours, especially battle-hardened Chadians, has tipped the balance against Boko Haram, whom the Nigerian military had been struggling to contain.