Boko Haram militants kidnapped hundreds of women and children from the northern Nigerian town of Damasak, which was recaptured from the Islamist group earlier this month by troops from Niger and Chad, reports said Tuesday, citing residents.

Although there was no official confirmation on the number of missing people, local residents reportedly said that more than 500 women and children had been abducted by the militants. Boko Haram’s six-year insurgency came to global attention in April when the group kidnapped nearly 300 schoolgirls from a boarding school in Chibok town in northeastern Nigeria's Borno state.

“They took 506 young women and children (in Damasak). They killed about 50 of them before leaving,” a trader, whose wife and three daughters were among those abducted, told Reuters. “We don’t know if they killed others after leaving, but they took the rest with them.”

Maina Maaji Lawan, the senator representing the north of Borno state, told BBC that the case in Damasak was typical.

“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,” BBC quoted Lawan as saying.

Boko Haram captured Damasak, which lies on Nigeria’s border with Niger, on Nov. 24, 2014. By the time it was recaptured, most of the residents had either deserted the town or had been killed, the New York Times reported.

Last week, troops from Niger and Chad found at least 70 bodies dumped in an apparent execution site under a bridge outside the town of Damasak. The bodies had been partially mummified while many were beheaded.

Boko Haram, which promotes a belief that taking part in any western political and social activity is “haram,” or forbidden for Muslims, had recently pledged allegiance to the Islamic State group. ISIS reportedly accepted the pledge, turning Boko Haram the third jihadist group outside Iraq and Syria -- after Ansar Bait al-Maqdis in the Sinai Peninsula and Shura Youth Council of Derna in Libya -- to join the so-called caliphate.