A mass grave has been discovered in central Mali just days after arrests by the military as it responds to increasing jihadist attacks in the region, Amnesty International said in a new report.
Concerns are growing about alleged abuses as Mali's military tries to stop extremism from spreading further in the west African nation.
Residents in the village of Dogo identified six bodies found in the mass grave as people who had been arrested on March 22 by the military, the human rights group said. It added that the victims appear to have been blindfolded.
"Military forces fighting armed groups have also committed crimes under international law including extrajudicial killings, enforced disappearances and arbitrary arrests," the group said.
On February 21, military forces arrested and blindfolded nine men in Daresalam, residents told the rights group. Two men from the Bambara ethnic group were released but seven Peulh men have not returned.
The United Nations mission in Mali has reported that at least 43 people were victims of enforced disappearances by Malian security forces during anti-extremist operations between May and June last year.
"Civilians in Mali are living in fear. We are urging the Malian authorities to investigate," said Gaetan Mootoo, Amnesty International's West Africa researcher.
Mali's military said it respects human rights.
"I see in these allegations that the international community is trying to justify its presence in Mali," said Col Diarran Kone, spokesman for Mali's army.
"The facts in question took place in an area of great community tension and it may be civilians who killed each other."
Col Kone said the latest killings are being investigated, adding: "I promise you that justice will be done."
Amnesty International said the discovery of the mass grave came after weeks of escalating violence in Mali's central Segou and Mopti regions, with civilians caught in the crossfire.
At least 65 people, including children, have been killed by explosives since January as jihadist groups step up attacks, the group said, with at least eight people still being held hostage.
Amnesty International called for increased protection of civilians, saying the insecurity has reached a crisis point. Hundreds of schools have closed in central and northern Mali, leaving more than 214,000 children without education.