Men dressed as soldiers opened fire on worshippers leaving a mosque in Nigeria's far northeast earlier this week, killing at least 35 people in the second such attack this month, officials said.
The attack in Demba village happened on Monday but details were only emerging on Friday because the area is remote and phone lines had been cut off by authorities to disrupt activities of the armed group Boko Haram.
Officials blamed Boko Haram for the attack which occurred close to Baga town in northeast Borno state, which was a stronghold of the group until a military crackdown in mid-May pushed many fighters into hiding or across the Cameroon border.
“It is impossible to access the area. Human rights and civil society groups are also being prohibited to visit the area where the army has launched an onslaught against the rebels,” Al Jazeera’s Yvonne Ndege, reporting from the capital, Abuja, said.
“What we were told by army is that these people were killed because they refused to join Boko Haram and worked against them.”
Defence spokesman Brigadier General Chris Olukolade told the AFP news agency that "Boko Haram people attacked the village on the ground that they have refused to cooperate with them, that they refused their message.
“The report that was presented has it that 35 people were killed and 14 wounded,” he said.
A separate military source said Boko Haram gunmen dressed as soldiers entered the village early on Monday and took up positions at a crossroads, where they fired upon worshippers leaving a mosque after morning prayers.
The source said the attack was believed to be in reprisal for a raid by soldiers and vigilantes in the village the previous week that resulted in the arrest of Boko Haram members.
The attack happened the same day the military said the group's leader Abubakar Shekau might have died between July 25 and August 4 from gunshot wounds inflicted in a gun battle with security forces.
Nigeria's military launched an offensive in the northeast in May against Boko Haram.
Attacks by the group and fighting against them have left more than 3,600 dead since 2009, including
killings by the security forces, who have been accused of major abuses.
Boko Haram has said it is fighting for the creation of an Islamic state in the country's north, though the group is believed to have a number of factions with varying aims.