Nigerian soldiers patrol in the north of Borno state close to a Boko Haram former camp on June 5, 2013 near Maiduguri
Maiduguri (Nigeria) (AFP) - Nigeria's military said Monday it had "besieged" Boko Haram positions in the Islamist militant group's northeastern heartland after setting free 178 hostages, mainly women and children.
The ongoing operation has led to the capture of a Boko Haram commander, according to the army, while a "large number" of the extremists have been killed in air strikes.
The hostages were released on Sunday near Aulari, about 70 kilometres (40 miles) south of Maiduguri, the capital of Borno state, once a jihadist stronghold.
"During the offensive operations, 178 people held captive by the terrorists were rescued. They include 101 children, 67 women and 10 men," military spokesman Colonel Tukur Gusau said.
The Nigerian military has announced the release of hundreds of people held by Boko Haram in recent months, many of them in the vast Sambisa forest, a longtime bastion of the Islamist group.
"The military operation... will continue until the terrorists are totally subdued. For now, we have besieged the forest and military operations are going on from different fronts," army spokesman Colonel Sani Usman told AFP.
He said the freed hostages were being screened and processed and would be reunited with their families after further security checks.
However the soldier was unable to give any details on the identity or rank of the Boko Haram commander seized in the operation to free the hostages, except that the militant was "undergoing interrogation".
Air strikes on Friday and Saturday hit the village of Bita on the fringes of the forest near the Cameroonian border, where Boko Haram was preparing to launch an offensive, the military said.
- Air strikes -
"A large number of them were killed while others ran away. We have have so far suspended air strikes," said air force spokesman Air Commodore Dele Alonge.
"But we have since carried out surveillance on Bita and other nearby towns and villages and we have returned to base."
Sunday's rescue came after several attacks by Boko Haram in recent days. Thirteen people were killed in an assault on Malari village about 20 kilometres from Maiduguri.
Local farmer Moha Saleh confirmed the death toll and said 27 people were wounded when the Islamists stormed the village.
"They also set many houses ablaze after accusing us of telling soldiers their whereabouts," he told AFP.
Villager Goni Musa, a vigilante who fights Boko Haram alongside the Nigerian military, gave the same death toll.
"This morning 13 bodies were recovered. Some had been shot in the back, which means they were fleeing when the terrorists killed them," Musa said.
"They burnt down houses and shops before they left, yelling 'Allahu Akbar' (God is greatest). Our terrorised women and children fled into the bush and returned to Maiduguri this morning," he added.
State police commissioner Aderemi Opadokun confirmed the attack but gave a lower toll, saying seven people had been killed.
Malari has been the target of numerous attacks in recent months, including a suicide bombing by a teenaged girl in a mosque in the middle of the Muslim holy month of Ramadan in July which left 12 people dead.
Many of the jihadist group's recent attacks have been carried out by women and girls.
- 'Blind terror' -
Boko Haram has increasingly expanded its operations into neighbouring countries in recent months, prompting Nigeria, Cameroon, Chad and Niger to launch a coordinated military fightback.
The four countries, along with Benin, are preparing to launch a new 8,700-strong force that officials say will go into action soon.
"The multinational joint force will eradicate... the blind terrorism of Boko Haram," Niger's President Mahamadou Issoufou said in a televised speech on Sunday.
The jihadist group has stepped up its attacks since Nigeria's new President Muhammadu Buhari took office in May, unleashing a wave of violence that has claimed 800 lives in just two months.
Witnesses said the group attacked the town of Gamboru on Saturday, near the border with Cameroon.
Residents in nearby villages said the militants had set fire to houses, sending columns of black smoke into the sky.
Umar Babakalli, a refugee from Gamboru who fled to the nearby Cameroonian town of Fotokol several months ago, said he saw fighter jets circling overhead "but there was no sign of any bombardment."
It was not immediately clear if anyone had been killed in Gamboru but Babakalli said the town, which has faced repeated Boko Haram assaults, was deserted.
"There is nobody in Gamboru," he told AFP.