The estimated death toll in the Ukraine conflict nearly doubled to at least 2,086 as of Aug 10 from 1,129 on July 26, the United Nations human rights office said on Wednesday.

"This corresponds to a clear escalating trend," UN human rights spokeswoman Cecile Pouilly told Reuters in response to a query.

On average, more than 60 people a day have been killed or wounded since fighting began in mid-April in eastern Ukraine, rising to at least 70 people a day in the first week of August, she said.

Nearly 5,000 have been wounded to date. The figures for casualties include Ukrainian soldiers, armed groups, insurgents and civilians, but are "very conservative estimates", Pouilly said.

"For instance, civilian casualties are likely to be under reported, due to the continuing insecurity which prevents affected people from getting access to medical aid ... and because communication channels have been disrupted," she added.

It was not clear whether Russian soldiers were included in the UN estimates for casualties which were based on information received from Ukrainian authorities as well as local medical facilities, Pouilly said. "We have no breakdown on nationalities or (civilian or military) status," she said.

Western countries and Kiev fear that Russian President Vladimir Putin - whose forces annexed Crimea from Ukraine in March - could now send them into the east to head off a humiliating rebel defeat.

Also on Wednesday, media reported that dozens of pro-government troops were killed in fighting with independence-seeking insurgents in eastern Ukraine since Tuesday.

Eleven Ukrainian army soldiers were killed and 41 injured during a day and night of the heavy battles in Donetsk and Lugansk regions, said Andrei Lysenko, a spokesman for Ukraine's National Security and Defense Council.

In a separate development, at least 12 pro-government fighters from the Ukrainian ultra-nationalist group Right Sector were reportedly killed when their convoy was ambushed by insurgents.

The representatives of the self-proclaimed "Donetsk People's Republic" confirmed that they carried out the attack against pro-government.

The Right Sector is a radical nationalist group, a key participant of the recent protests in Kiev, which toppled the former authorities and is now fighting against insurgents in eastern Ukraine along with government forces.

(China Daily 08/14/2014 page12)