Boko haram extremists attack Nigeria
The terror group committed the killings in the city of Ngambu in the northeastern Borno State YouTube

Nigeria's military has confirmed a ceasefire has been agreed with the Islamist militant group Boko Haram and the kidnapped Chibok schoolgirls are to be released.

The deal was announced by Nigeria's chief of defence staff, Air Marshal Alex Badeh, according to Nigeria's official news agency.

Badeh has ordered Nigerian troops to immediately respect the ceasefire agreement. The terror group is yet to make a public statement on the deal.

Nigerian presidential aide Hassan Tukur revealed that the truce was finalised after one months of negotiations between the two parties, mediated by Chad.

"They've assured us they have the girls and they will release them," he said. "I am cautiously optimistic."

In April, 276 schoolgirls were kidnapped from a school in the town of Chibok in Borno State. Over two hundred remained missing before the announcement of the ceasefire.

In return for the schoolgirls' release, the Islamist militants have been demanding the release of detained fighters for the group.

'We should remain cautious'

Andrew Noakes, coordinator of the Nigeria Security Network, said: "If confirmed, this ceasefire would be unprecedented in the history of the conflict. It will bring great relief and hope to the parents of the kidnapped Chibok girls, as well as to millions of people in northern Nigeria who face constant danger due to the insurgency.

"However, we should remain cautious in welcoming this news. Boko Haram is a fragmented organisation, and it's unclear which factions have signed up to this deal," he added.

"We also have to wonder what the Nigerian government has given away in exchange. Boko Haram is likely to have demanded money, arms, and the release of captured fighters. Such a transfer would only increase the insurgency's operational capacity in future."

Three northeastern states - Yobe, Adamawa and Borno - have been placed under a state of emergency since May last year because of the terror group's insurgency.

According to Human Rights Watch, the militants have killed at least 2,053 people since the beginning of 2014 but researchers at the John Hopkins University School of International Studies estimate that 7,000 people have been killed in the 12 months between July 2013 and June this year.