Human rights group, Amnesty International, has accused the M23 rebels fighting in the eastern Democratic Republic of Congo (DRC) of possible war crimes.
In a report published on Tuesday, it claimed the Rwanda-back militants were responsible for killing, torturing, and forcibly disappearing civilian detainees in areas under its control.
The NGO said these serious abuses violate international humanitarian law and may amount to war crimes.
The decades-long conflict in the eastern Congo escalated in January, when the M23 rebels began a rapid advance.
They seized swathes of territory in the region, including the strategic city of Goma in North Kivu province, followed by Bukavu in February.
Amnesty says that earlier this year, it interviewed 18 former detainees in the two cities, 9 of whom had been tortured by M23 fighters.
The civilians said they were accused of supporting the Congolese army or government, but that the rebels provided no proof. Some were not told why they were being held.
Eight detainees said that they witnessed fellow detainees die in detention, likely from torture and harsh detention conditions.
They said hundreds were held in overcrowded, unsanitary cells without sufficient food, water, sanitation facilities or healthcare.
Most were held incommunicado and denied access to their families and to lawyers.
Amnesty is calling on the M23 to immediately release arbitrarily detained civilians, and said the rebel group should treat prisoners humanely and provide them with access to lawyers and their families.
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Hundreds of civilians have been killed in clashes between M23 rebels and the Armed Forces in Goma. The fighting has driven more than 1.7 million people from their homes in North Kivu.
M23 is one of about 100 armed groups that have been vying for a foothold in mineral-rich eastern DRC, in a conflict that has created one of the world’s most significant humanitarian crises.
Despite Congo’s army and M23 having agreed to work toward a truce last month, fighting between the two sides continues.
