Boko Haram waged fresh attacks in northeastern Nigeria, locals said Friday, bringing to nearly 170 the number of people killed this week in violence President Muhammadu Buhari blasted as "inhuman and barbaric".
Militants have launched multiple attacks in restive Borno state since Wednesday, with people attending evening prayers during the holy month of Ramadan gunned down, women shot at home, and men dragged from their homes in the dead of night.
A young female suicide bomber also killed 12 worshippers when she blew herself up in a mosque in Borno and while there was no immediate claim of responsibility, Boko Haram has used both men and young women and girls as human bombs in the past.
"President Muhammadu Buhari has condemned the latest wave of killings by Boko Haram in Borno state, describing them as most inhuman and barbaric," the presidency said in a statement.
The wave of attacks, which took place over less than 36 hours, is the bloodiest since Buhari came to power in May, vowing to root out the insurgency that has claimed more than 15,000 lives.
Bodies 'lying unattended'
News of the violence first emerged on Thursday, when survivors described raids on three different villages in Borno the previous evening that left at least 145 people killed and houses burnt to the ground.
On Friday, fresh details of these killings emerged from a resident of Kukawa, the worst-affected village.
Baana Kole told AFP that he and others had managed to escape into the bush where they spent the night, before returning to bury the dead, only to find that the militants had laid mines everywhere.
"Some residents who hid in trees saw them planting the mines and alerted us when we returned to the village and started burying our dead," he said.
"So many dead bodies are still in Kukawa lying unattended. We had to abandon them because we could not carry them with us."
Bomber 'aged around 15'
Less than 24 hours later, a girl blew herself up in a mosque in Malari village, more than 150 kilometres away from Wednesday's attacks.
"The bomber was a girl aged around 15 who was seen around the mosque when worshippers were preparing for the afternoon prayers," Danlami Ajaokuta, a vigilante assisting the military against Boko Haram, told AFP.
"People asked her to leave because she had no business there and they were not comfortable with her in view of the spate of suicide attacks by female Boko Haram members.
"She made to leave but while the people were inside the mosque for the prayers she ran from a distance into the mosque and blew herself up," he added -- an account corroborated by resident Gajimi Mala.
And early Friday morning, as people were sleeping, Boko Haram militants dragged men out of houses in Miringa village and shot them for escaping forced conscription.
They "picked 13 men from selected homes and took them to the Eid prayer ground outside the village where they opened fire on them," resident Baballe Mohammed said, adding 11 died and two managed to escape.
He and another resident said the victims had been targeted because they had fled their home village after Boko Haram tried to force them to join their ranks.
Boko Haram has 're-grouped'
The armed group has intensified its campaign of violence since Buhari came to power on May 29, launching raids, explosions and suicide attacks that have claimed more than 420 lives.
The spike in violence has sparked concern that earlier victories claimed by the armies of Nigeria, Niger, Chad and Cameroon in the region are being eroded.
The four countries -- all of which border Lake Chad, a focal point of Boko Haram unrest -- launched offensives against the militants early this year as it became apparent that the armed group was gaining too much ground in Nigeria.
They managed to push the militants out of captured towns and villages, but the recent attacks highlight that Boko Haram is not defeated.
"The draw-down of counterinsurgency initiatives, in addition to the fact such undertakings remain limited to Nigerian territory only, have seemingly allowed Boko Haram to re-group, re-arm and mobilise their forces ahead of a renewed offensive," said Ryan Cummings, chief Africa analyst at the Red24 consultancy group.
A new regional fighting force comprising 8,700 troops from Nigeria, Niger, Chad, Cameroon and Benin is due to deploy at the end of the month.