Hundreds of people are feared dead in a suspected Boko Haram attack on four villages in northeast Nigeria, in the latest upsurge in violence claiming increasing numbers of civilian lives.

Some community leaders put the death toll from the Tuesday attacks in the Gwoza district of Borno state as high as 400 to 500, although there was no independent verification because of poor communications in the remote area.

Four people were killed on Thursday near the home of a state governor in northeast Nigeria when a pick-up truck loaded with grain bags exploded, a government source told Agence France Presse.

The blast happened at about 6:30 pm (17:30 GMT) near the private residence of Gombe state governor Ibrahim Dankwambo in the upscale Government Reserve area of the state capital.

Suspected Boko Haram militants Thursday a fresh raid on a town in the restive northeast of Nigeria, firing on soldiers and burning down a church, a local government official said.

"There was an attack on Madagali town this morning by gunmen suspected to be Boko Haram insurgents," Maina Ularamu, chairman of the Madagali local government in Adamawa state, told AFP.

Supporters of more than 200 schoolgirls kidnapped by Islamist militants headed to court on Tuesday to challenge a police ban on protest marches in the Nigerian capital, calling the decision illegal.

The Bring Back Our Girls campaign said it would seek to overturn the ban, which the Federal Capital Territory police announced on Monday because of what they said were security concerns.

A bomb attack targeting fans at a football match in Nigeria's restive northeast killed at least 40 people on Sunday, a police officer told Agence France Presse.

"There has been a bomb explosion at a football field this evening and so far more than 40 people have been killed," said the officer who requested anonymity in the town of Mubi, which has seen previous attacks by Boko Haram Islamists.

Two Italian priests and a Canadian nun seized by suspected Boko Haram gunmen in Cameroon two months ago have been freed, a security source told Agence France Presse Sunday.

The hostages were "freed overnight, at about 2 in the morning. Our soldiers picked them up from a village close to Amchide," in the north of the country, the Cameroonian security source said.

A series of suspected Boko Haram attacks in four villages in Nigeria’s restive northeast killed several people, residents said Sunday, in the latest violence blamed on the Islamist insurgents.

The military was not immediately available to comment on the raids in Borno state, the hardest hit area during Boko Haram’s five-year extremist uprising, which has killed thousands.

The West African bloc announced plans Saturday to increase cooperation with Central African states in the battle against "terrorism", amid fears of Boko Haram's insurgency spreading across the region.

Nigeria has repeatedly said it needs more help from its central African neighbors -- including Chad, Cameroon and Niger -- to end the brutal five-year insurgency being waged by the Islamists.

Boko Haram gunmen on Friday killed a Nigerian Islamic monarch in their northeastern stronghold of Borno in an attack that also targeted two other Muslim royals who escaped unhurt, the state government said.

The Emir of Gwoza, Idrissa Timta, was shot dead in the Tashan Alade area of Borno state while traveling by road to the funeral of another senior cleric, Borno's government said. 

Nigerian President Goodluck Jonathan Thursday vowed "total war against terrorism" following last month's mass abduction of schoolgirls by Boko Haram Islamists amid news of attacks in three border villages that claimed 35 lives.

Jonathan said in an address marking 15 years since the return of civilian rule to Nigeria that no efforts would be spared to rescue the more than 200 girls kidnapped from a school in the northeastern town of Chibok in Borno state on April 14.