UNHCR's European director Vincent Cochetel said local Ukrainian authorities had so far registered some 117,000 people leaving the east for other regions of Ukraine, AFP reports.
Cochetel told reporters in Geneva that the number "is in our view a low estimate," since most men fleeing failed to register to avoid being drafted into the Ukrainian Army and sent back to the conflict zone.
Cochetel said that, in addition, around 168,000 Ukrainians had as of August 1 applied to Russian authorities for asylum, refugee, and other kinds of protective status such as temporary residence permits.
The total of at least 285,000 displaced people marks a 24 percent jump from figures provided by the UNHCR last month.
Cochetel said that, according to Russian authorities, some 730,000 Ukrainians have gone to Russia since January under the country's visa-free regime, without registering.