The U.N. mission report obtained by Reuters states this, Censor.NET informs.
The report by the 34-member U.N. monitoring mission, prepared by the U.N. human rights office in Geneva, also cited reports of human rights violations by Ukraine's military forces and special battalions run by the country's Interior Ministry.
The report said the death toll has risen to at least 2,200 since the fighting began in mid-April, with an average of at least 36 people killed daily. That is up from at least 2,086 on Aug. 10 and 1,129 on July 26.
"Armed groups continue to commit killings, abductions, physical and psychological torture, ill treatment, executions, murder and other serious human rights abuses," the report said, adding that violations were "disproportionately targeting civilians."
At least 468 people are believed to be held captive by rebels, according to the report, which covers the period from July 16 to Aug. 17.
"The Ukraine military has reported shelling from (Russian) territory ... and of the illegal use of landmines in Ukraine territory," the monitors said.
The reported abuses by the Ukrainian military and special Interior Ministry battalions include "arbitrary detention, enforced disappearances and torture," the report said.