ABUJA (Reuters) - Islamist fighters from Nigeria’s Boko Haram group have abducted more than 1,000 children in the northeast since 2013, the United Nations children’s agency UNICEF said on Friday.

The militants regularly took youngsters to spread fear and show power, the agency said on the eve of the fourth anniversary of the abduction of 276 schoolgirls from the town of Chibok, a case that triggered global outrage.

“Children in northeastern Nigeria continue to come under attack at a shocking scale,” said Mohamed Malick Fall, UNICEF’s Nigeria head.

The agency said it had documented more than 1,000 verified cases, the first time it had published an estimated tally. But the actual number could be much larger, it added.

It said it had interviewed one young woman, Khadija, now 17, who was abducted after a Boko Haram attack on her town, then locked in a room, forced to marry one of the fighters and repeatedly raped.

She became pregnant and “now lives with her young son in an IDP (displaced persons) camp, where she has struggled to integrate with the other women due to language barriers and the stigma of being a ‘Boko Haram wife’,” UNICEF said.

At least 2,295 teachers have been killed and more than 1,400 schools have been destroyed in the conflict, it added.

POLITICALLY CHARGED

The Boko Haram conflict is in its tenth year, but shows little sign of ending. In February, one faction kidnapped more than 100 schoolgirls from the town of Dapchi, previously untouched by the war.

A month later, the militants returned almost all of those girls. About five died while in Boko Haram hands. One other, Leah Sharibu, remains captive because she refused to convert to Islam, her freed classmates have said.

The government said the release was a prelude to ceasefire talks, though some insurgency experts disagree, saying it violated that faction’s ideology to kidnap Muslims.

Boko Haram remains a charged issue politically. President Muhammadu Buhari in 2015 rode to power on promises to end the insurgency. But his administration has failed to defeat Boko Haram, despite pushing the militants out of many towns in the northeast by 2016.

On Monday, Buhari said he plans to seek re-election in 2019.

Four years since the Chibok abduction, about 100 of the schoolgirls are unaccounted for. Some may be dead, according to testimony from the rescued girls and Boko Haram experts.

Boko Haram in January released a video purporting to show some of the missing Chibok girls, saying they wish to remain with their captors.