The members of the civilian joint task force (CJTF) were waiting for soldiers at Kayamla village, in the Konduga area of Borno state.
The members of the civilian joint task force (CJTF) were waiting for soldiers at Kayamla village, in the Konduga area of Borno state, northeast Nigeria, when the attack happened.
"We lost eight comrades in an ambush by Boko Haram gunmen at about 5:30 am (0430 GMT)," said CJTF member Ibrahim Liman in the state capital Maiduguri, which is 10 kilometres (six miles) away.
"The vigilantes had gone to Kaymala as an advance party that was to be joined later by troops to launch an attack on Boko Haram enclave.
"Unknown to them, Boko Haram terrorists, who by all indications had prior knowledge of the offensive, ambushed them by climbing into the trees.
"They opened fire on the team as soon as they pulled over."
Liman's account was supported by another militia member, Musa Ari, who helped to bury his fallen comrades.
"We buried the last of the eight victims this evening. The bodies were recovered from Kayamla by soldiers," he added.
Konduga district is a known hotbed of Boko Haram activity, despite government and military claims that the jihadists are a spent force, having been forced out of their Sambisa Forest enclave in Borno state.
In May, four CJTF members hunting in the bush near a camp for those displaced by the Islamist insurgency had their throats slit on the outskirts of Maiduguri.
Two of their colleagues were also killed when two female suicide bombers detonated explosives in Konduga town, some 35 km from Maiduguri by road.
The attacks came just days after Boko Haram gunmen on motorbikes killed six farmers working on their land in Amrawa village, also on the outskirts of the state capital.
In April, eight loggers were killed and their bodies burnt near Kayamla village.
In a new video published on Saturday, Boko Haram claimed responsibility for its first raid inside Maiduguri in about 18 months, which left 11 people dead on Wednesday.
At least 20,000 have been killed since the insurgency began in 2009.