It is being reported a deal has been reached in Nigeria to release more than 200 kidnapped schoolgirls, who were taken by Islamist militants.

Military officials say a truce has been agreed with militant group Boko Haram.

219 girls were kidnapped - and allegedly sold as slaves - prompting an international appeal for their freedom

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

"I have accordingly directed the service chiefs to ensure immediate compliance with this development in the field."

The president's principal secretary Hassan Tukur told the AFP news agency that an agreement to end hostilities had been reached after talks with the Islamist group.

He said: "Boko Haram issued the ceasefire as a result of the discussions we have been having with them.

"That have agreed to release the Chibok girls."

The talks are thought to have taken place in neighbouring Chad, with the country's president Idriss Deby mediating negotiations.

Boko Haram kidnapped more than 200 girls at gunpoint from a school in Chibok, northeastern Nigeria, on April 14.

Some of the girls managed to escape from the group in the aftermath of their kidnap or during fighting among militants, but 219 remain missing.

Mr Jonathan has faced strong criticism over a deteriorating security situation in Nigeria, with areas in the northeast Borno state inaccessible due to the threat from Boko Haram.

The group has demanded the release of detained extremists in exchange for the girls.