The UN has warned on Friday of soaring rights violations in Sudan's western Darfur region amid escalating fighting seven months into the war between the army and paramilitaries.
"We have received these reports from new arrivals in Chad, these are refugees fleeing the Darfur area, that are talking about armed militia going from house to house killing men and boys," spokesman William Spindler told reporters in Geneva.
"These killings reportedly have happened in the last few days," he added.
Ardamata among other things houses a camp for people displaced inside Sudan, where UNHCR said nearly 100 shelters had been razed to the ground.
It also warned in a statement that "extensive looting" had taken place, including of UNHCR relief items.
UNHCR chief Filippo Grandi pointed to the dark history in the region, where a long war and atrocities began two decades ago after the government of Omar Al Bashir unleashed the Janjaweed group in response to an uprising.
"Twenty years ago, the world was shocked by the terrible atrocities and human rights violations in Darfur," Grandi said in a statement.
"We fear a similar dynamic might be developing," he warned.
"An immediate end to the fighting and unconditional respect for the civilian population by all parties are crucial to avoid another catastrophe," he said.
The refugee agency voiced alarm at reports of continued sexual violence, torture, arbitrary killings, extortion of civilians and targeting of specific ethnic groups in the region.
It also highlighted reports that thousands of already displaced people had been forced to flee a camp in the West Darfur state capital of El Geneina.
UNHCR said it was preparing for a new flood of refugees from the region into Chad, which is already hosting hundreds of thousands of Sudanese refugees.
"More than 8,000 people have fled into neighbouring Chad in the last week alone," UNHCR said, adding that this figure was likely to be an underestimate due to challenges registering new arrivals.
Since April, forces loyal to army chief Abdel Fattah al Burhan have been at war with the paramilitary Rapid Support Forces (RSF) commanded by Mohamed Hamdan Dagalo.
More than 10,000 people have been killed in the Sudan conflict so far, according to a conservative estimate by the Armed Conflict Location & Event Data project.
But aid groups and medics have repeatedly warned the real toll exceeds recorded figures, with many of those wounded and killed never reaching hospitals or morgues.
The war has displaced more than 4.8 million people within Sudan and has forced a further 1.2 million to flee into neighbouring countries, according to UN figures.