MINNA, Nigeria (AFP) — Some 130 Nigerian Catholic school pupils were handed over to state authorities on Monday, a day after the government said it had secured their release a month after one of the country’s worst mass abductions.

Kidnappings for ransom are a common way for armed groups to make quick cash in the conflict-hit west African nation of some 230 million, but a spate of attacks in November put an uncomfortable international spotlight on Nigeria’s grim security situation.

Six vans of children were escorted by security forces in armoured vehicles to the Niger State Government House, an AFP reporter in the state capital Minna saw Monday.

Authorities said the children, along with seven teachers and support staff, were the last batch of those taken by gunmen in the late November mass abduction at the St. Mary’s co-educational boarding school in north-central Nigeria.

“Thank God for the mercy he has shown us, because if you look at these children and imagine the torment they went through, it is unbearable,” Niger state Governor Mohammed Umaru Bago said at the reception ceremony.

The children were between four and 10 years old, one of the teachers told AFP at the scene.

Scores of children, including young boys sporting brightly-coloured football jerseys and others wearing traditional Nigerian clothes, posed for photos at the state government office where they were handed over by security forces.

The attack on St Mary’s — reminiscent of the infamous 2014 kidnapping of schoolgirls by Boko Haram in Chibok — was part of a series of mass abductions that rocked the west African country last month.

Nigeria suffers from multiple interlinked security concerns, from jihadists in the northeast to armed “bandit” gangs in the northwest.

It has not been publicly disclosed who abducted the children and teachers from St Mary’s, or how the government secured their release.

Analysts have said that based on past rescues, it is likely the government paid a ransom, which is technically prohibited by law.