A vigilante group claiming to help authorities battle insurgents in Nigeria's northeast has set fire to a top politician's home after accusing him of links to Islamist extremist group Boko Haram, residents said Tuesday.

Nigeria's military has welcomed and encouraged the vigilante group in its fight against Boko Haram, but Monday's incident in the city of Maiduguri illustrated the risks in allowing it to operate.

Several dozen vigilantes targeted the home of Mala Othman, state chairman of the ANPP party, an opposition party nationally but which controls power in Borno state, where Maiduguri is located.

They wanted him to surrender, but he had apparently escaped through the back of the house.

"The youth armed with clubs and sticks chanted 'we will finish terrorists' and set fire to the house when Othman did not show up," one witness said.

"He and his family scaled the fence at the rear and escaped."

Other residents reported similar accounts. The military did not respond to requests for comment.

Some local media reported that the mob later went to the home of former Borno governor Ali Modu Sheriff, but soldiers fired in the air to disperse them, reports said.

Sheriff and other ANPP officials have been repeatedly accused of using local gangs to help rig elections who later morphed into elements of Boko Haram. They deny the allegations.

Boko Haram has a number of different factions in addition to imitators and criminal gangs who commit violence under the guise of the group.

Violence linked to the insurgency has left some 3,600 people dead since 2009, including killings by the security forces.

Nigeria's military launched a major offensive seeking to end the insurgency in May and later welcomed the involvement of the local vigilantes.

It however spoke of "the need for caution in order to ensure that the process is not used to settle scores or witch-hunt perceived enemies".