Armed men abducted 287 students from an elementary and secondary school in Nigeria's northwest on Thursday, reports said Friday.

A teacher, Sani Abdullahi, told the regional broadcaster in Kaduna State that 187 pupils from the secondary school and 125 from the primary school in Kuriga were initially listed as missing after the attack on Thursday morning. Of these, 25 had since been found.

On Friday morning, 287 pupils, both girls and boys, were still missing, along with a teacher.

The Boko Haram terrorist militia and other groups have carried out abductions in northern Nigeria since 2014. The abductions are aimed at extorting money, forcing recruitment into the ranks of armed groups or sex slavery.

Abdullahi related how the men had surrounded the school at the start of the day, forcing 700 pupils and their teachers into a nearby woodland area. Many had been able to escape, he said.

A local civil protection group attempted to follow the group, and one of them was killed in the operation.

Kaduna Senator Uba Sani confirmed the abductions but did not provide details on the number of abducted. He assured that "all steps have been taken to ensure the safe return of the pupils and students."

A tearful Kuriga councilor told the broadcaster of the poor security situation in the region. Over recent months, smaller groups, mainly women and children, had been abducted in the state, he said.

A mass abduction took place in Borno State in the far north-east of Nigeria at the end of last month. The U.N. estimated the number to be more than 200, although the precise number remains unknown.