Damasak, Nigeria: Residents in the northern Nigerian town of Damasak said on Tuesday that Boko Haram militants kidnapped more than 400 women and children as they left the town, which was freed by troops from Niger and Chad this month.

‘They took 506 young women and children. They killed about 50 of them before leaving,’ a trader called Souleymane Ali told Reuters in the town.

‘We don't know if they killed others after leaving, but they took the rest with them.’

Lieutenant Colonel Toumba Mohamed, the Nigerien commander of the Niger-Chad forces in Damasak, said residents had reported between 400 and 500 women and children kidnapped.

He said: ‘The very young ones they give to madrassas… and male ones between 16 and 25, they conscript them and they indoctrinate them as supply channels for their horrible missions.’

Boko Haram caused international outrage in April 2014 after it abducted more than 200 girls from a boarding school in Chibok town in north-eastern Nigeria's Borno state.

The group's leader Abubakar Shekau has said the girls have been married off.

Chadian soldiers drive in the recently retaken town of Damasak, Nigeria, 18 March 2015.

Regional troops have played a key role in recapturing territory from Boko Haram.

The group is opposed to children receiving a secular education, alleging that it corrupts their religious beliefs.

Damasak is a trading town in Borno state near Niger's border and is about 200km (120 miles) from the state's main city of Maiduguri.

It was overrun by the militants, who began their insurgency in 2009 to create an Islamic state, at the end of last year.