Gunmen on Wednesday killed at least nine people and set fire to dozens of houses in central Nigeria, the army and police said, in the latest violence to hit the region.

The early morning raid happened in four mostly Christian communities in the Riyom local government area of Plateau state, which has seen a spate of sectarian attacks over recent years.

Ex-army general Mohammed Gusau formally took charge of Nigeria's defense ministry on Wednesday, a choice analysts said may lead to a change in strategy in the raging battle against Boko Haram.

The defense post had been vacant since June 2012, when President Goodluck Jonathan sacked Mohammed Bello following a spate of deadly attacks by the Islamist insurgents.

Suspected Islamist insurgents killed 29 people in Nigeria's embattled northeast, an official said Monday, the latest carnage in a surge of violence that has left more than 100 dead this month alone.

The latest attack on Sunday hit the town of Mafa in Boko Haram's historic stronghold of Borno state, which is witnessing one of the deadliest episodes of the group's nearly five-year-old rebellion.

At least 35 people were killed following two explosions in a crowded neighborhood of Nigeria's restless northeastern city of Maiduguri, a stronghold of Boko Haram Islamists, police said Sunday.

"We are still counting. So far we have counted 35 bodies. Our men are still working with rescue workers at the scene," Borno state police commissioner Lawal Tanko told Agence France Presse.

Two explosions on Saturday rocked the northern Nigerian city of Maiduguri, a stronghold of the radical Islamist Boko Haram group, residents said.

The blasts hit a densely populated area of the city and sent residents fleeing in panic.

Sporadic gunfire sparked panic on Friday as the governor of Nigeria's Adamawa state met with survivors of a brutal Islamist attack, a spokesman said.

Governor Murtala Nyako traveled from the state capital Yola to visit those targeted in Wednesday's coordinated assault blamed on Boko Haram rebels that killed at least 37 people in three locations.

Nigeria's presidency on Friday said the country was at war with Boko Haram, apparently backing off previous claims that the Islamist rebels were on the run and desperate.

President Goodluck Jonathan's administration has been fiercely criticised over its handling of the conflict, both for its inability to stop massive attacks on defenseless civilians and for what some have described as mixed and contradictory messages on the severity of the crisis.

Suspected Boko Haram gunmen killed at least 32 people in three separate attacks in northeast Nigeria, including at a theological college, a local government official and residents said on Thursday.

The coordinated attacks in Adamawa state late on Wednesday came just a day after Islamist militant fighters were blamed for killing 43 people, most of them students, as they slept at a boarding school in Yobe state.

Security issues threatened to overtake the festivities as President Francois Hollande arrived in Nigeria on Thursday for centenary celebrations, as calls mount for French help against Islamist Boko Haram militants.

Just hours before Hollande touched down, hundreds of suspected militant fighters laid siege to a town in Adamawa state in northeast Nigeria, destroying scores of homes and businesses with heavy weaponry and explosives.

Scores of suspected Boko Haram Islamists armed with grenade launchers and explosives razed a town in Nigeria's embattled northeast, killing two people, including a child, witnesses told Agence France Presse on Thursday.

Residents in Michika, in Adamawa state, said people fled to the nearby foothills when the attackers dressed in military uniforms stormed the town in four-wheeled drive trucks and motorcycles.