Forty-five people were killed by suspected Boko Haram gunmen pretending to be preachers in a village near the group's spiritual home in northeast Nigeria, two residents said on Thursday.
The attack happened at about 9.30pm (2030 GMT) on Wednesday in Barderi, on the outskirts of Maiduguri, and saw insurgents hoodwink locals into congregating before opening fire on the crowd.
Itinerant preaching is commonplace in mainly Muslim northern Nigeria and the fake clerics reportedly told villagers that they had come to show them "the righteous path".
Mallam Bunu, who survived the attack, said: "I counted 45 bodies after the attackers left the village.
"They came to our village... and lied to us that they had come to preach to us and when almost all the villagers had gathered, another set of insurgents emerged from nowhere and opened fire on the congregation before we all scampered for safety."
Another survivor, Kallamu Bukar, said: "When we converged, another set of insurgents emerged from nowhere and joined those that were disguised as preachers.
"They opened fire on the congregation. The assailants also set ablaze several houses, shops and other personal effects."
The attacks came after Boko Haram gunmen rampaged through four villages in the far-flung Gwoza district in Borno state on Tuesday.
A local member of parliament described the attacks, which carried on into Wednesday, as "massive" while local community leaders said hundreds of people may have been killed.
Gunmen also burned down a Roman Catholic church and a local government office in Madagali in neighbouring Adamawa state on Thursday morning.
Borno, Adamawa and Yobe state have been under a state of emergency since May last year but apparent initial gains in forcing Boko Haram out of urban centres appear to have been lost.
Attacks now occur on an almost daily basis in remoter border regions, increasingly against civilians, often due to the perception that local vigilante groups are assisting the military.