The Human Rights Watch (HRW) organization has documented the first war crimes of the Russian Federation against Ukrainians in the occupied territories of Chernihiv, Kharkiv and Kyiv regions, HRW has said in its report.

"These include a case of repeated rape; two cases of summary execution, one of six men, the other of one man; and other cases of unlawful violence and threats against civilians between February 27 and March 14, 2022. Soldiers were also implicated in looting civilian property, including food, clothing, and firewood," HRW said in the report published on Sunday.

"Those who carried out these abuses are responsible for war crimes," the human rights organization said.

"The cases we documented amount to unspeakable, deliberate cruelty and violence against Ukrainian civilians," Hugh Williamson, Europe and Central Asia director at Human Rights Watch said.

Human Rights Watch interviewed 10 people, including witnesses, victims, and local residents of Russia-occupied territories, in person or by telephone.

"On March 4, Russian forces in Bucha, about 30 kilometers northwest of Kyiv, rounded up five men and summarily executed one of them;… Russian forces in the village of Stary Bykiv, in Chernihiv region, rounded up at least six men on February 27, and later executed them;… On March 6, Russian soldiers in the village of Vorzel, about 50 kilometers northwest of Kyiv, threw a smoke grenade into a basement, then shot a woman and a 14-year-old child as they emerged from the basement, where they had been sheltering;... a Russian soldier had repeatedly raped her in a school in Kharkiv region where she and her family had been sheltering on March 13," according to the report.