Nigeria's military and presidency on Friday claimed to have reached a deal with Boko Haram militants on a ceasefire and the release of more than 200 kidnapped schoolgirls.

"A ceasefire agreement has been concluded between the Federal Government of Nigeria and the Jama'atu Ahlis Sunna Lidda'awati wal-Jihad (Boko Haram)," Chief of Defense Staff Air Marshal Alex Badeh said.

Nigeria can hold elections in February even if Boko Haram violence makes voting impossible in parts of the northeast, the country's elections chief told AFP, arguing that the disenfranchisement of thousands of people would not undermine the entire vote.

Attahiru Jega, who heads the Independent National Electoral Commission (INEC), said he was preparing to organize polling in the three states under emergency rule because of Islamist attacks.

Fifty-nine Nigerian soldiers appeared before a military tribunal on Wednesday charged with mutiny and conspiracy to commit mutiny over claims that they refused to fight Boko Haram militants.

The soldiers, all members of the 111th Special Forces Battalion, all pleaded not guilty at a general court martial sitting in the capital, Abuja.

Nigeria's former military ruler, Muhammadu Buhari, on Wednesday put fighting insecurity and corruption at the top of his bid to become president, as he formally launched his campaign for leadership.

The 71-year-old announced that he was standing for the presidential ticket of the main opposition All Progressives Congress (APC), which he said was "resolved to bring change to Nigeria".

Nine teenage girls died and three were listed missing after a passenger boat capsized on a river in northern Nigeria, an emergency services official said on Wednesday.

‎‎"We have recovered nine bodies of the girls and we are still searching for the remaining three," Usman Ado of Kano State Emergency Service Agency told Agence France Presse.

Protesters demanding the release of 219 Nigerian schoolgirls held by Boko Haram militants were set to mark the six-month anniversary of their abduction Tuesday with a defiant march on the Nigerian presidency.

Six months since the kidnapping of the teenagers, interest in their plight has waned despite an initial wave of international outrage.

A coroner's inquest was opened and adjourned in Nigeria on Monday into the deaths of scores of people who were killed at the church of a popular evangelical preacher and televangelist.

Coroner Oyetade Komolafe told the hearing in Lagos that more time was needed to enable all parties to prepare evidence and present witnesses.

The Islamic State jihadist group says that it has given Yazidi women and children captured in northern Iraq to its fighters as spoils of war, boasting it had revived slavery.

The latest issue of its propaganda magazine Dabiq released on Sunday was the first clear admission by the organisation that it was holding and selling Yazidis as slaves.

Ten Chinese and 17 local hostages have been released in Cameroon, where they were kidnapped earlier this year in raids blamed on the Nigerian Islamist group Boko Haram, Cameroon's president said Saturday.

"The 27 hostages abducted on May 16 in Waza and July 27 in Kolofata were released to the Cameroonian authorities this night," President Paul Biya said in a statement on national radio.

Boko Haram militants killed seven people on Monday in the remote northeast of Nigeria, residents and an official said, with reports indicating the victims were beheaded in a revenge attack.

The overnight raid targeted the town of Ngamdu in troubled Borno state, the area hardest hit in the Islamists’ five-year uprising.