Armed soldiers and police are patrolling the central Nigerian town of Makurdi after an anti-police riot.
Police fired in the air to disperse protesters and dismantled roadblocks.
The riots began after a bus conductor was shot dead by police - allegedly during an argument following a request for a bribe.
A reliable source told the BBC's Yusuf Sarki Muhammad in the Nigerian capital, Abuja, that the body of a second man has also been found.
The bus conductor was the second person to be killed by police in two weeks, following the shooting of a 19-year-old girl.
The officers who shot the conductor have been arrested, officials say.
There are few details about the violence but there are unconfirmed reports that two police stations were burnt to the ground.
Our correspondent says the anti-police riots are bad news for newly appointed police chief Sunday Ehindero, who has promised a people-friendly police force.