At least 24 members of a vigilante group in northeastern Nigeria have been killed in an ambush during a botched attempt to arrest Boko Haram members, security officials said.
The officials said fighters from the rebel group wearing army uniforms ambushed more than 100 vigilantes on Friday.
"They were ambushed even before they got to the Boko Haram camps," one of the youth vigilantes Masta Moh'd, who was not present during the attack near the town of Monguno in Borno state, but had heard from several of the survivors, told the Reuters news agency on Saturday.
He said more than 100 of the vigilantes had participated in the raid, which turned sour when the fighters, seen as the main security threat to Africa's top energy producer, ambushed them as they entered the town's outskirts.
Officials claim another 34 people are missing after the attack.
A member of the government's mixed military and police Joint Task Force, who declined to be named, confirmed the death toll from the incident as 24.