An independent UN commission found reasonable grounds to conclude that war crimes and human rights violations were committed in Ukraine since the beginning of the war in late February.
UN political affairs chief Rosemary Di Carlo told the Security Council that the Independent International Commission of Inquiry on Ukraine submitted its report to the General Assembly this week and found Russian troops responsible for the vast majority of violations identified.
But it also found that Ukrainian forces have violated international humanitarian laws in some cases.
The commission documented patterns of summary executions, unlawful confinement, torture, ill-treatment, rape and other sexual violence committed in areas occupied by Russian armed forces.
Di Carlo said more than 6,000 civilians were killed in Ukraine, including 397 children. A total of 9,634 people have been injured.
''The actual figures are likely considerably higher,'' she added.
She expressed ''grave'' concern about the destruction of critical energy infrastructure following recent Russian strikes across Ukraine.
''Combined with soaring gas and coal prices, the deprivation caused by these attacks threatens to expose millions of civilians to extreme hardship and even life-endangering conditions this winter,'' she said.
About 30% of energy facilities have been hit since Oct. 10 in the Kyiv, Dnipropetrovsk, Lviv, Kharkiv and Sumy regions, according to the Ukrainian government.