According to a report released by UN High Commissioner for Human Rights Navi Pillay, the conflicts have also displaced over 100,000 people.
It also voices concern over escalating violence in eastern Ukraine, saying that armed groups continue to abduct, detain, torture and execute people in the restive Lugansk and Donetsk regions, Xinhua reported.
The bloody standoff led to the collapse of the rule of law, the report says, urging both sides of the conflict to put an end to violence and restore respect for human rights.
Heavy fighting in eastern Ukraine has also caused serious damage to civilian property and infrastructure, it said, estimating that Kiev would have to raise at least $750 million in funding for the rebuilding and revitalising the region.
The crisis in eastern Ukraine began in mid-April, when Kiev launched offensives against pro-Russian militants in a bid to retake the cities and towns seized by them. Since then, the government forces have taken control of more than 20 municipalities.
Last week, Ukraine said it lost 325 of its troops during the military operation.