The UN refugee agency says at least 285,000 people have fled their homes because of the conflict in eastern Ukraine, as Russia called for an emergency UN Security Council meeting on the crisis.
UNHCR's European director Vincent Cochetel said local Ukrainian authorities have so far registered some 117,000 people leaving the east for other regions of Ukraine.
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.
He noted that the number of people who left the separatist-controlled regions of Luhansk and Donetsk in eastern Ukraine rose abruptly from 2,600 in early June to 102,600 at the beginning of August.
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.
Cochetel said the agency believed "that number is credible."
The UNHCR said that around 80 percent of Ukrainians in Russia are staying in the country's border areas, while some are moving to stay with friends or relatives in other parts of the country.
Meanwhile, Russia's UN Ambassador Vitaly Churkin called on August 5 for the UN Security Council to hold an emergency meeting on the Ukrainian crisis amid reports of intense fighting in the rebels' main bastion of Donetsk.
The city's local council said fighting was under way and explosions were heard in the Petrovksy district as well as in other parts of the city.
In Kyiv, Ukrainian President Petro Poroshenko said that over the past two months, the territory controlled by separatists in the east "has shrunk by three-fourths."
In a separate development, Andriy Lysenko, a spokesman for the national defense council, said separatists opened fire on unarmed Ukrainian soldiers on August 5 as they crossed back into Ukraine from Russia where they had taken shelter from fighting.
Lysenko had no immediate word on casualties.
Ukraine acknowledged on August 4 that 311 soldiers and border guards had been forced by fighting with separatists to cross into Russia.
With reporting by AFP and Reuters