YENAGOA, Nigeria, Oct 12 (Reuters) - A group of 15 Nigerian women and children trekked through the bush for six days to escape from Islamist militants who had kidnapped them from churches in the northeast, a state governor said.

Northeast Nigeria has been ravaged for more than a decade by a conflict between Islamist insurgents and the armed forces, in which an estimated 300,000 people have been killed and thousands abducted, some held in captivity for years in remote camps.

Other women who have escaped or been rescued have recounted being forced to marry their abductors and bear their children, among other abuses.

Governor Babagana Zulum of Borno State said the six women and their nine children were being held by the Islamic State West Africa Province (ISWAP) group in a forest in Buni Yadi, an area of Yobe State, until they escaped and walked for six days to the town of Damboa in neighbouring Borno.

Zulum met the women and children on Monday, and they were due to be reunited with their families, according to a post on his Facebook page. They were abducted in 2020 and 2021, the governor's post said.

Three of the women had been kidnapped from the Chibok area in Borno, where in a separate attack in 2014 fighters from the Boko Haram group had kidnapped 270 girls from their school, drawing global condemnation.

The other three women had been abducted from the village of Cofure in Adamawa State, south of Borno.

Buni Yadi was the scene of one of the worst atrocities in the conflict, the killing of 59 pupils who were shot or burned to death in their boarding school in 2014.

The Nigerian authorities say thousands of Boko Haram fighters have surrendered to the security forces.

The group's leader Abubakar Shekau died in May after detonating a bomb while he was being pursued by ISWAP fighters following a battle. ISWAP was originally an offshoot of Boko Haram but the factions have turned on each other.