The Nigerian army released 566 persons, including 355 babies, held by Islamist militant group Boko Haram in several camps across northeastern Borno state.

They were handed over on Friday to the state's governor Kashim Shettima at a rehabilitation centre run in partnership with the UN's children agency, Unicef, where they will receive medical care, reporters attending the ceremony were told.

Nigeria has been grappling with Boko Haram since 2009, when it began an insurgency that has killed tens of thousands of people in a bid to impose its version of Islamic law.