Local residents, speaking on condition of anonymity, said last week that the attack was a reprisal for violence last October.
The United States has agreed to sell fighter jets to Nigeria to help in its fight against Boko Haram.
Famine has been ongoing since last year in parts of Nigeria where the government is fighting a seven-year long Boko Haram insurgency.
Amnesty International says the army killed unarmed members of a group calling for secession.
CARTOON: Meanwhile, elsewhere...
More than 2,000 schools have been shut down in north east Nigeria and its neighboring countries.
Officials are hunting for those behind multiple bomb blasts which killed almost 50 people.
The blast was set off by a suicide bomber targeting traders at a fruit & vegetable market.
A blast struck a market in the northeastern Nigerian city of Yola killing 32 people and wounding 80 others.
