Eighteen men arrested by soldiers in north-east Nigeria have been found dead hours after being taken into custody, residents in the town of Potiskum say.
All the bodies had gunshot and knife wounds, they said.
The men had earlier been accused of being members of the militant Islamist group Boko Haram.
The Nigerian military has denied killing them and announced the release of more than 40 others who had been suspected of links with the militants.
Two residents of Potiskum, who told the BBC they had identified 18 bodies in the town's morgue, said the men had been arrested on Wednesday by the Nigerian military during a search operation.
A nurse at the morgue was quoted by AFP news agency as saying the bodies had been brought in by soldiers.
The news agency said community leaders believed the men had been killed because they were from the Kanuri ethnic group from which Boko Haram draws many of its members.
They have demanded an inquiry into the deaths.
"We believe they were killed on suspicion of being Boko Haram because they were Kanuris," AFP quoted an unnamed community leader as saying.
Another said: "The government should look into this cold-blooded murder and ensure justice is done because being a soldier is not a licence to kill at will on mere suspicion."
Potiskum is the commercial centre of Yobe state and has been the scene of many attacks by Boko Haram, including a suicide bombing on Monday in which 15 people died.
The Nigerian army has been conducting a war against the group and has frequently been accused of committing atrocities itself, including torture and beheadings.
It denies doing so.
In the city of Maiduguri, which has been at the centre of the insurgency, the army said it had released 42 people who had earlier been accused of being members of Boko Haram.
They were given more than $1,000 (£631) each by the military and the local government.