UN rights chief ‘shocked’ by reports that Nigerian and Chadian forces killed more than 100 civilians and seeks investigations.

The United Nations human rights chief has demanded independent investigations into reports that separate air attacks by the Nigerian and Chadian forces in northern Nigeria killed more than 100 civilians.

Nigeria’s military ‌has been battling “bandits” in the northwest, often describing them as “terrorists”. It has also been battling ‌an ‌armed rebellion in the northeast for 17 years.

The Nigerian military and the “bandit” gangs killed at least 100 civilians on Sunday in one of the bloodiest days in the state’s conflict against armed groups, according to Amnesty International.

Citing witnesses, Amnesty said many of those killed were women and children, and urged authorities to immediately investigate the attack on a crowded market in Tumfa village.

“I am shocked by reports that Nigerian army airstrikes on a market in Zamfara state killed at least 100 civilians on 10 May and injured many more,” UN High Commissioner for Human Rights Volker Turk said in a statement.

He said he was also “alarmed and saddened” by the reports of high civilian casualties in attacks since Friday by Chadian jets against Boko Haram camps on remote islands in the vast marshland shared by Nigeria, Cameroon, Niger and Chad.

The bombardment has reportedly killed dozens of Nigerian fishermen working on islands under Boko Haram control, where civilians are forced to pay taxes to the armed group. Footage verified by the AFP news agency showed several fishermen with severe burns being treated at a hospital in Bosso, Niger.

“It is crucial that both Nigerian and Chadian authorities conduct prompt, thorough, independent and impartial investigations into these disturbing incidents,” Turk said, adding that both militaries must “take all feasible precautions to avoid harm to civilians”.

“Their military operations, including against Boko Haram and the so-called ‘Islamic State West Africa Province’ must be conducted in full compliance with international humanitarian law and international human rights law,” he said, referring to the ISIL (ISIS) affiliate in West Africa Province (ISWAP). “Civilians and civilian objects must never be the target of attack.”

Meanwhile, the Nigerian military said on Wednesday ⁠that there ⁠has been no evidence of civilian casualties in attacks in the ⁠northwest Zamfara state this month, calling reports of large death tolls unverified and misleading.

“No credible, substantiated evidence of civilian casualties has been established through any official assessment or independent ⁠verification,” defence headquarters spokesman Major-General ⁠Michael Onoja said in a statement.

Onoja claimed that the strike was conducted under international humanitarian law and targeted a “confirmed high-level gathering” based on intelligence sources in a village where “several terrorists were neutralised”.