GENEVA -- Around three dozen people a day are being killed in eastern Ukraine where both sides target civilians in violation of international law and the death toll has risen to at least 2,220, the UN human rights office said Friday.

The latest findings from the Geneva office, based on reports from a 34-member UN monitoring mission in Ukraine, show both sides committing a range of abuses targeting civilians trapped in urban areas or trying to flee through so-called safe corridors.

Pro-Russian rebels in Ukraine have carried out murders, torture and abductions along with other serious human rights abuses and violations of international humanitarian law, according to the mission's field work between July 16 and Aug. 17. But the report says Ukraine's military also is responsible for human rights violations such as arbitrary detentions, disappearances and torture.

The head of the Geneva office, UN High Commissioner for Human Rights Navi Pillay, raised alarm over the killings in Ukraine.

"Deliberate targeting of civilians is a violation of international humanitarian law and more must be done to protect them," she said.

As of two weeks ago at least 468 people believed to be detained by the various armed groups, the report says, while the Ukrainian government has arrested more than 1,000 people in the country's east on charges of taking part in terrorist activities.

UN Assistant Secretary-General for Human Rights Ivan Simonovic said in Kyiv on Friday that ill-treatment of hostages had been "well-documented," and that the parading of hostages "are acts that fuel tension and hatred."

Rebels have prevented people from leaving cities that caught up in the fighting, he said. "They are in a sense using whole towns and cities as human shields."

Simonovic also noted "disturbing reports of violations" by government forces.

"The battalions have replaced the police in many of the newly liberated town and villages ... reports of arbitrary detention, forced disappearance and torture have continued," Simonovic said.

"The government must exercise more control over all its forces, including the volunteer battalions."