A UN human rights report says there has been "limited accountability" in eastern Ukraine for arbitrary killings and torture by separatist fighters and Ukrainian soldiers.
"Impunity for killings remains rampant, encouraging their perpetuation and undermining prospects for justice," said the report, issued on July 14 by the Office of the United Nations High Commissioner for Human Rights (OHCHR).
The report was based on research into the killings of more than 9,400 people in Ukraine's Donbas region since fighting started there in 2014 through May 2016.
"Accountability will be key to the establishment of sustainable peace in Ukraine," said UN High Commissioner for Human Rights Zeid Ra’ad al-Hussein. "This is the only way forward, as has been fully and tragically demonstrated by the many countries which have not dealt properly with serious international crimes and human rights abuses."
UN investigators found evidence of arbitrary killings by Russia-back separatists, Ukrainian troops, police forces, and volunteer battalions of fighters.
The report cited executions of prisoners by both sides and indiscriminate shelling of civilian areas using imprecise weapon systems.
The OHCHR said some of the killings of civilians could be considered "war crimes."
Although some of the people involved in arbitrary killings have been prosecuted, the OHCHR said many investigations into deaths are delayed or left unfinished.
The report said probes into killings in separatist-held areas of Ukraine's Donetsk and Luhansk regions appear to be selective and suspects are not guaranteed a fair trial.