The United Nations says the conflict in Ukraine has forced more than 800,000 people from their homes.
UNHCR, the UN refugee agency, told a briefing in Geneva that an estimated 430,000 people were currently displaced within Ukraine -- 170,000 more than at the start of September.
It said at least 387,000 have asked for refugee status, temporary asylum, or other forms of residency permits in Russia.
Another 6,600 have applied for asylum in the European Union and 581 in Belarus.
Around 95 percent of displaced people come from eastern Ukraine, where government troops have been battling pro-Russian separatists.
The agency said it was "racing to help some of the most vulnerable displaced people" as winter approaches.
It also said the number of displaced people is expected to rise further due to ongoing fighting in eastern Ukraine.
The country is bracing for an uptick in violence ahead of parliamentary elections on October 26.
The United States has urged all Ukrainians, including those in rebel-controlled areas in the east as well as the illegally annexed Crimean peninsula, to cast their ballot.
A follow-up vote is scheduled for December 7.
State Department spokeswoman Jen Psaki called the weekend election "another milestone" for Ukraine and said Washington would "strongly condemn any interference" in the election.
Pro-Russian rebels in the eastern regions of Donetsk and Luhansk are vowing to hold their own separate elections in November.
Ukrainian Prime Minister Arseniy Yatsenyuk has voiced concerns that Russia may attempt to disrupt the October 26 elections.
Yatsenyuk told a meeting of top security officials and election monitors on October 23 it was "absolutely clear that attempts to destabilize the situation will continue and will be provoked by Russia."
He called for the "full mobilization of the entire law-enforcement system" to prevent election fraud and possible violence during the vote.
Interior Minister Arsen Avakov said some 82,000 policemen will be deployed on election day.
Yatsenyuk's warning comes on the heels of three violent attacks on parliamentary candidates in the past week.
The latest, against Volodymyr Borysenko, a member of Yatsenyuk's People's Front Party, occurred on October 20 when Borysenko was shot at and had an explosive thrown at him.
He allegedly survived the attack only because he was wearing body armor due to numerous death threats he had recently received.
Polls show President Petro Poroshenko's party leading with some 30 percent of respondents saying they would cast their vote for the Petro Poroshenko Bloc.