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.
A concerted military crackdown on the armed rebel group, Boko Haram, ordered by President Goodluck Jonathan in mid-May, had appeared to have weakened the armed group, but they have repeatedly proved masters at going into hiding then coming back just as deadly as before.
|Civilians dead among Nigeria offensive
The use of civilian vigilantes - often armed with no more than clubs and knives - as a weapon against the fighters has led to the arrest of hundreds of them, the military says.
That civilian backlash against Boko Haram has handed the military its greatest advantage over the uprising in the four years it has been active.
It has also made the vigilantes and their families prime targets for the armed group. Scores have been killed in revenge attacks.
The military said this month that Boko Haram's leader Abubakar Shekau may have died in late July of wounds inflicted during a fire fight with them, although they gave no evidence.
If he is dead, it appears not to have quelled the violence, which is on the rise since the start of the month.