Kano - Several female suicide bombers blew themselves up in the midst of fleeing residents in the northeast, continuing a series of attacks that have killed some 200 people in just three days, witnesses said Saturday.
The latest attack took place Friday night in Zabarmari village, 10 kilometres (six miles) from the city of Maiduguri, birthplace of the jihadist group.
Local resident Haladu Musa, who fled the attack to Maiduguri, told AFP that "large numbers" of fighters poured into the village, overpowering government forces deployed to prevent the insurgents reaching Maiduguri.
"The soldiers were forced to retreat," he said.
Then, as people began to flee, female suicide bombers started blowing themselves up in their midst, killing large numbers of people, he said.
"Most of the casualties came from the suicide bombings," he said, without being able to give a precise figure for the dead and injured.
Musa said the militants looted shops and torched "almost half the village" before eventually being repulsed after the military sent in reinforcements.
Danlami Ajaokuta, a civilian vigilante helping the military battle Boko Haram and who also witnessed the attack, spoke of heavy casualties.
"The main concern now is to evacuate and attend to the injured and later recover the dead bodies now lying in the village," he said, adding that more than 100 people had been hospitalised with injuries.
Boko Haram, which is fighting to establish a hardline Islamic state in northeast Nigeria and has sworn allegiance to the Islamic State group, has intensified its campaign of violence since President Mohammadu Buhari came to power on May 29.
The Zabarmari attack followed a series of attacks across restive Borno state since Wednesday that have been blamed on the jihadists.
This week, militants gunned down worshippers at evening Ramadan prayers, shot women in their homes and dragged men from their beds in the dead of night.
A young female suicide bomber also killed 12 worshippers when she blew herself up in a mosque.
Buhari condemned the attacks as "inhuman and barbaric" and again vowed to end the Islamists' six-year-old insurgency which has killed at least 15,000 people and displaced 1.5 million others.
The spike in violence has sparked concern that earlier gains by the armies of Nigeria, Niger, Chad and Cameroon against the militants are being eroded.
The four countries -- all of which border Lake Chad, a focal point of Boko Haram unrest -- took the fight to the militants early this year to try claw back some of the territory they had gained in the northeast.
The armies managed to push the militants out of several towns and villages, but the recent attacks show the group to be far from defeated.
A new regional force comprising 8,700 troops from Nigeria, Niger, Chad, Cameroon and Benin is due to deploy at the end of the month.