At least 2,000 girls and women have been kidnapped by Boko Haram Islamic militants since last year and turned into cooks, sex slaves and fighters.
Those who refused to comply were killed, Reuters reported Wednesday, citing Amnesty International.
In a 90-page report, the human rights group detailed Boko Haram’s atrocities from dozens of interviews with witnesses and escaped abductees a year after militants seized more than 200 schoolgirls from Chibok in a self-proclaimed Islamist caliphate in northeastern Nigeria.
The kidnapping, and a video showing the captured girls dressed in dark hijabs soon afterwards, provoked international outrage.
But the majority are still missing despite Western pledges to help track them down and a Chadian attempt to broker their release.
Boko Haram’s leader, Abubakar Shekau, claims the girls had been “married off” to his fighters.
Amnesty’s report said Boko Haram routinely rounded up women and girls after taking control of a town and held them in houses or prisons.
A 19-year-old woman told Amnesty how she had been abducted at a wedding in September 2014 alongside the bride and the bride’s sister and then held at a training camp in Madagali alongside hundreds of female fighters.
“I was among the girls trained to shoot. I was also trained how to use bombs and how to attack a village,” said the woman, who was gang-raped several times by the guerillas and wished to remain anonymous.
She told Amnesty some of those who refused to covert to Islam or to fight were dumped in a mass grave.
Many men who refuse to join Boko Haram’s ranks have also been killed.
Two young men told researchers that at least 100 were executed in one day in December when the armed group took over Madagali. They survived because the killers’ knives had become too blunt to slit more throats.
“These appalling executions, the sexual violence, the recruitment of child soldiers, these are war crimes and crimes against humanity and they need to be investigated [by the Nigerian authorities],” Daniel Eyre, author of the report, said in an interview.
Boko Haram is thought to have killed thousands of people in its six-year insurgency but Nigerian troops alongside neighboring armies from Chad, Cameroon and Niger have won back vast swathes of territory from them in recent weeks.
Muhammadu Buhari, Nigerias presient-elect who beat Goodluck Jonathan in an election two weeks ago and has vowed to squash Boko Haram, said on Tuesday the girls’ whereabouts is unknown but that he would try to locate them.
“As much as I wish to I cannot promise that we can find them. But I say to every parent, family member and friend of the children that my government will do everything in its power to bring them home.”
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