(CNN) Human Rights Watch is accusing Iraqi Kurdish forces of unlawfully targeting and destroying Arab homes in regions they have retaken from ISIS fighters.

Kurdish Regional Government forces, also known as the Peshmerga, is a 100,000-strong military force, backed by the United States in its mission to drive out ISIS from Iraq.

The US-based human rights group released a report Sunday detailing at least 21 attacks carried out by Kurdish fighters on villages with mixed Kurdish and Arab residents between September 2014 and May 2016 in disputed parts of Kirkuk and Nineveh, governorates in northern Iraq. Researchers spoke to witnesses on the ground and say they found destroyed Arab buildings next to intact Kurdish-owned ones.

"In village after village in Kirkuk and Nineveh, KRG security forces destroyed Arab homes -- but not those belonging to Kurds -- for no legitimate military purpose," said Joe Stork, deputy Middle East director at Human Rights Watch.

Satellite imagery from 62 villages show evidence of destruction after Kurdish forces recaptured them from ISIS but a lack of presence on the ground in those areas make it difficult to independently confirm if they were indeed destroyed by Kurdish troops.

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