The United Nations human rights office has condemned both sides fighting in Ukraine for killing civilians in indiscriminate shelling.
The report released by the UN's High Commissioner for Human Rights office says up to 2,000 civilians have died in the two-year conflict in eastern Ukraine between government forces and Russia-backed rebels, nearly 90% of them in shelling of residential areas.
The authors cited executions by both Ukrainian forces and rebel groups of "significant numbers" of people who allegedly were affiliated with, or sympathetic to, the other side and of fighters who had surrendered or were out of action.
The report also claimed to have found cases of Ukrainian servicemen intentionally killed for revealing abuses by Ukrainian forces.
It also noted that no arrests have been made over the fatal shooting of 13 policemen in the capital Kiev during the final days of the massive street protests that drove Ukraine's Russia-friendly president to flee.
The human rights office said it was concerned that authorities had not conducted an effective investigation into the deaths of 48 people in the city of Odessa on a day of clashes in 2014 between supporters of the new pro-Western Ukrainian government and their opponents.
Some 42 of those died in a fire at a building where anti-government demonstrators had taken shelter. Many believe the blaze was started by firebombs thrown into the building.
Fiona Frazer, head of the UN human rights monitoring mission for Ukraine, said that her office has been in contact with the government about the report.
"There needs to be strong investigation in order to identify perpetrators of crimes committed, to bring justice to the victims and their families to end the continued suffering, and at the end of the day to ensure there is accountability in this country," she said.
Overall, the UN says more than 9,400 people have died in the conflict in eastern Ukraine since it broke out in the spring of 2014.