He added, “These include wanton killings, summary executions, forced participation in military operations – including the use of children to detonate bombs, forced labour, forced marriage and sexual violence, including rape.”

The High Commissioner cited a series of eyewitness reports which recounted incidents in which children who were suspected of theft had had their hands amputated; of a man stoned to death on accusations of fornication; and mass executions of captives whose hands and legs were bound and who were dumped into rivers and wells.

According to the press release, in another case of Boko Haram's particular brutality, the militant group ordered the inhabitants of Kwajafa village in Borno state to gather and hear them preach. When the villagers did gather, the insurgents opened fire.

The extremists allegedly perpetrated a similar crime against the male inhabitants of Mararaba Madagali in Adamawa state in late 2014 when they assembled and killed at least 1,000 men and boys who had refused to join the group’s “depraved cause,” the UN official added.

Against that backdrop, the High Commissioner voiced concern over what his office described as “extremely worrying reports” regarding the actions of Nigerian armed forces during their anti-Boko Haram offensive.

“My predecessor, Navi Pillay, during her visit to Nigeria last year said that many of the people she met openly acknowledged that human rights violations had been committed by the security forces, and that these have served to alienate local communities and created fertile ground for Boko Haram to cultivate new recruits,” he continued.

“Since then we have continued to receive reports of arbitrary arrests and detention, torture and summary executions, as well as of a failure to take adequate measures to ensure the protection of civilians during counter-insurgency operations.”

The High Commissioner acknowledged the enormous challenges facing the Nigerian Government and voiced encouragement over the efforts of newly-elected President Buhari to “leave no stone unturned to promote the rule of law and ensure justice and the protection of human rights while countering terrorism.”

Nevertheless, he urged the Government to establish “proper independent inquiries” into alleged violations of international human rights and international humanitarian law by the Nigerian armed forces, including into the “deeply disturbing allegations” that thousands of people have died or been killed while held in detention by State institutions.

“Investigations into human rights violations must be conducted in a transparent manner, in order to inspire confidence and deter further violations,” the High Commissioner concluded. “This is crucial to ensure that victims of Boko Haram’s crimes are not doubly victimized by their own Government.”

Photo: OCHA/Caroline Birch