At least 415,800 people have fled their homes due to fighting between government forces and pro-Russian separatists in eastern Ukraine, the UN refugee agency said on Wednesday.
According to the latest UNHCR estimates, at least 190,000 have been displaced within Ukraine, while 197,400 have fled to Russia. A further 14,600 have travelled to Poland and 13,883 to Belarus.
"We do recognise that the number of displaced could be higher as there's no centralised registration system and we know that some people are not registering,"- said Ariane Rummery, a spokeswoman for the UN agency.
The number of displaced has risen dramatically over the past month as the government in Kiev has intensified its offensive against rebel strongholds in eastern Ukraine.
More than 2,000 people have been killed and 5,000 injured since fighting began in April.