Boko Haram kidnapped Eight more Girls in Borno State.

Suspected Boko Haram gunmen have kidnapped eight more girls, aged between eight and 15, in an overnight raid on a village in the sect's stronghold in north-eastern Borno state.

The attack came a day after the group released a video threatening to sell as "slaves" 276 teenage schoolgirls kidnapped three weeks ago.

In another village, militants shot at least 52 people in a separate revenge attack against residents who were collaborating with security officials.

"They were many, and all of them carried guns," Lazarus Musa, a resident of Waraba where the attack happened on Monday night, told Reuters. "They came in two vehicles painted in army colour. They started shooting in our village. The Boko Haram men were entering houses, ordering people out of their houses."

"They just came in and started shooting. They said we locals had been collaborating with the security officials because it is true some of us went to the military post and told them where they keep their guns," said Abubakar Garba, a taxi driver in Gamborou. "Even now we are trying to recover some bodies, there were so many of them. The market smells of death and smoke."

The scale and audacity of the 15 April mass abductions in remote Chibok – several truckloads of militants were able to run rampant for almost five hours has shocked Nigerians and provoked a series of protests. In Abuja, about 500 people marched through the streets wearing red T-shirts and singing protest songs.

Officials have scrambled to provide explanations. On Sunday Patience Jonathan, the president's wife, accused local officials of being partially responsible for the attacks by opening Chibok school, even though others in the area had shut down.

African leaders have rallied around Nigeria. "All of us are fathers, and I could just imagine that my daughter could be one of them," said Ghana's president, John Dramani Mahama, who added he had written a letter on behalf of 14 other west African nations offering assistance.

William Hague, the British foreign secretary, said the UK was offering Nigeria assistance in recovering the girls who were being "treated as spoils of war by Boko Haram".