Suspected Boko Haram Islamists disguised in army uniforms killed seven people in an attack near the northeastern border with Cameroon, residents said Monday.

The gunmen, five of whom were also killed, razed a police station and a military camp during the late Sunday attack in the restive region, which has been among the hardest hit areas during Boko Haram's five-year uprising.

"The gunmen split into three groups and launched simultaneous attacks on the military camp, the police station and other buildings in the village," said Abor Grema, a resident of the targeted Krenuwa village in Marte district.

Marte was one of the areas in Borno state where Boko Haram chased out the government last year, forcing President Goodluck Jonathan to declare a state of emergency in the region while launching a military offensive to crush the uprising.

Six residents were shot dead during Sunday's raid, while a member of a local vigilante force which has formed to help the military was also killed, said Grema.

His account was supported by other witnesses including Musa Bulama, who said the gunmen torched homes, a police station, a military camp, homes and shops. "Five of (the Islamists) were killed and five others were captured,"

during fierce gun battles that followed the raid, according to Bulama.

A vigilante was "dragged from his home and slaughtered... on the streets" by extremists who returned to Krenuwa later in the night to seek revenge against locals who had fought with the military. Police and military spokesmen were not immediately available to comment on the attack.

Escalating violence along the border and Boko Haram attacks within Cameroon have led to calls for a more coordinated regional effort against the insurgents.

Nigeria has long said that Boko Haram fighters flee across Cameroon's porous borders to evade capture after carrying out attacks. The latest unrest in the region came after the escape of 63 women and girls kidnapped by the Islamists in June in Damboa, reportedly while their captors were battling the security forces.

The military claimed that it killed 53 Islamist rebels during the Friday clashes. The 219 girls seized by Boko Haram from a secondary school in April are still missing.