Among potential crimes against humanity, the UN-backed report cited repeated attacks targeting Ukrainian infrastructure since the fall that left hundreds of thousands without heat and electricity during the coldest months.

"There were elements of planning and availability of resources which indicate that the Russian authorities may have committed torture as crimes against humanity," said Erik M?se, a former Norwegian Supreme Court and European Court of Human Rights judge who led the investigation.?

Earlier, a UN panel led by Eric had found signs of beating of detainees, electric shocks, forced nudity, and sex- and gender-based violence even on minors by Russian personnel. Separately, Ukrainian First Lady Olena Zelenska said in November that Russian forces were using rape as an instrument of war.

The UN-backed investigation also found crimes committed against Ukrainians on Russian territory, including deported Ukrainian children who were prevented from reuniting with their families, a "filtration" system aimed at singling out Ukrainians for detention, and torture and inhumane detention conditions.

The significance of the report

A commission of inquiry is the most powerful tool used by the UN-backed Human Rights Council to scrutinise abuses and violations around the world. The investigation released Thursday was set up during an urgent debate shortly after Russia's invasion last year.

The commission's three members are independent human rights experts, and its staff gets support and funding from the council and the U.N. human rights office.?

The report's authors noted a “small number” of apparent violations by Ukrainian forces, including one they said was under criminal investigation by Ukrainian authorities, but reserved the vast majority of their report for allegations against Russia.

Russia did not respond to the inquiry's appeals for information.

Most of the abuses highlighted by the investigation were already well known, and the report is far from the first to accuse Russia of war crimes. However, the inquiry's findings come with the imprimatur of the international community: The experts work under a mandate overwhelmingly created last year by the Human Rights Council, which brings together the governments of 47 U.N. member countries.

Mose, who served as president of an international tribunal established to prosecute genocide cases from the massacre of members of Rwanda's ethnic Tutsi minority in 1994, said investigators have created a list of individuals to hold accountable for human rights violations in Ukraine.?

Mose said the list would be "submitted to the relevant authorities in this issue,” but the team acknowledged the difficulty of investigations involving a permanent member of the U.N. Security Council.?

Ultimately, the report may add to efforts to boost accountability for crimes committed in the war — whether by the International Criminal Court or by some individual countries that have taken on the right to apply “universal jurisdiction” to prosecute atrocities, wherever they may take place.?

Reports of Russian war crimes

Earlier in September, it was reported that Mose-led investigators had visited 27 towns and settlements as well as graves and detention and torture centres. They interviewed more than 150 victims and witnesses and met with advocacy groups and government officials.

Mose said at the time that an unspecified number of Russian soldiers were found to have committed crimes of sexual or gender-based violence. The victims ranged between 4-82-years-old.

Separately, in areas subsequently vacated by Russians or liberated by Ukrainians, mass graves have been found as a sign of alleged massacres by Russians.

Separately, Ukrainian First Lady Olena Zelenska said in November that Russian forces were using rape as an instrument of war.

Zelenska said sexual violence is most cruel way to assert mastership over a person. She added that that Russians have used it as a weapon of war "systematically and openly".

"Sexual violence is the most cruel, most animalistic way to prove mastership over someone...This is another instrument that they [Russian forces] are using as their weaponry. This is another weapon in their arsenal in this war and conflict. That's why they're using this systematically and openly," Sky News quoted Zelenska as saying at the time.

(With AP inputs)