Witnesses say Nigerian soldiers have shot dead more than 30 people in the city of Maiduguri, the home base of the militant group known as Boko Haram.
Residents of the city say soldiers from Nigeria's Joint Task Force (JTF) carried out the killings during raids on several neighborhoods late Thursday.
A source in the city morgue said he came to work Friday to find that the bodies of about 40 young men had been dropped off.
The JTF spokesman for Borno state, Sagir Musa, said he was not aware of the incident and is currently outside Maiduguri.
Rights groups Amnesty International and Human Rights Watch have accused the JTF of extra-judicial killings as the force tries to crush Boko Haram. The JTF has denied the allegations.
Boko Haram, a shadowy militant group, wants to impose Islamic law across northern Nigeria and is blamed for the death of more than 1,400 people since 2009.
Some information for this report provided by AP and Reuters.