U.S.-backed Kurdish forces in northern Iraq are deliberately destroying Arab villages and houses in a “revenge” campaign for the latter’s perceived support to the Islamic State group, Amnesty International alleged, in a report released Wednesday. In the report, which is based on field investigations, eyewitness interviews and perusal of satellite images, the human rights group said that these actions “may amount to war crimes.”

“KRG [Kurdistan Regional Government] forces appear to be spearheading a concerted campaign to forcibly displace Arab communities by destroying entire villages in areas they have recaptured from IS in northern Iraq,” Donatella Rovera, Amnesty’s senior crisis response advisor, said, in a statement accompanying the report. “Tens of thousands of Arab civilians who were forced to flee their homes because of fighting are now struggling to survive in makeshift camps in desperate conditions. … by barring the displaced from returning to their villages and destroying their homes KRG forces are further exacerbating their suffering.”

The rights group quoted a local resident, Maher Nubul, as saying that he left his village, Tabaj Hamid, in August 2014 when Islamic State fighters captured it. Four months later, when Kurdish forces recaptured the territory, the whole village was “flattened.”

“All I know is that when the Peshmerga retook the village the houses were standing,” Nubul said. “And later they bulldozed the village, I don’t know why. There is nothing left. They destroyed everything for no reason.”

Satellite images corroborated eyewitness accounts, Amnesty said. These images also showed large-scale destruction of homes in Nineveh, Kirkuk and Diyala provinces.

Since ISIS militants swept through northern Iraq in 2014, Kurdish Peshmerga forces, backed by the U.S. and its Western allies, have been at the forefront of a concerted offensive against the Sunni militant group. The Kurds, aided by U.S.-led airstrikes, have, over the past year, driven the militants back in the north, and expanded their control to reclaim ethnically mixed territories in the country.

While Amnesty acknowledged that the Kurds in Iraq had faced “unprecedented” humanitarian and security challenges since the rise of ISIS, it said that these “cannot excuse deliberate destruction and other serious abuses” committed by Kurdish forces, sometimes in collaboration with Yazidi militias and armed groups from Syria and Turkey.

“KRG forces have a duty to bring to justice in fair trials individuals who are suspected of having aided and abetted IS crimes. But they must not punish entire communities for crimes perpetrated by some of their members or based on vague, discriminatory and unsubstantiated suspicions that they support IS,” Rovera said, in the statement.

However, Kurdish officials denied the allegations leveled against their forces, and accused Amnesty of compiling its report based on testimonies by “people linked to ISIS.”

“They accuse us because they lost their territory in the fight against ISIS,” Jabbar Yawar, a spokesman for the Kurdish peshmerga, reportedly said. “Those who worked on the report compiled it from a unilateral point of view and did not ask the peshmerga about the contents of the report, whether or not the information was true.”