Thirty teenage girls and boys have been kidnapped since Wednesday from villages around Mafa town, 40 kilometres (25 miles) from the Borno state capital, Maiduguri, the local government chairman Shettima Maina told reporters.
Escaping residents said Boko Haram insurgents abducted 80 girls and women from neighbouring Adamawa state on October 18.
Older women in the group were released the following day and said the extremists kept about 40 younger women and girls, according to the residents. They spoke on condition of anonymity for fear of retaliation by the insurgents.
But the insurgents have launched several attacks since then and on Friday a multinational force including troops from Nigeria and Niger wrested back control of a town held by Boko Haram on the western shores of Lake Chad.
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Witnesses and a security official said more than 20 insurgents were killed in fierce fighting at Abadam in which the Nigerian Air Force bombed occupied posts and ground troops opened fire after which the insurgents fled.
Boko Haram had hoisted their black and white flag in Abadam a week before, when they killed at least 40 civilians and forced hundreds in the farming community to flee across the border into Niger, according to some residents who escaped to Maiduguri, 200 kilometres (125 miles) to the east.
No one claimed responsibility but suspicion immediately fell on Boko Haram, which in December 2011 bombed Azare's police station and several banks.
The continued fighting and abductions raise questions about the cease-fire. Ten days after the announcement, Boko Haram has yet to indicate that it has agreed to a truce.
Officials had said the cease-fire would lead to the speedy release of the 219 girls kidnapped from a boarding school in the remote northeastern town of Chibok on April 15.
The insurgents mainly target Christians and girls who go to school, said Human Rights Watch.
More than 500 girls and women have been kidnapped by Boko Haram since 2009, according to an estimate by the New York-based rights group.