Ukrainian opposition leader Viktor Yanukovich called on his rival Yulia Tymoshenko to concede defeat on Monday after a narrow victory in the presidential election.
His call came with more than 98 percent of the vote counted from Sunday's poll and as international election monitors declared the election an "impressive display" of democracy.
Had the monitors raised any doubts about the conduct of the election it could have prompted legal action by Ms Tymoshenko, the prime minister. In the run-up to polling day she criticised changes in electoral law which she said would allow the poll to be manipulated. Ms Tymoshenko cancelled a scheduled press conference.
The count gave Mr Yanukovich - the humiliated loser of the country's 2004 Orange Revolution - a margin of 2.8 per cent over his opponent.
A Yanukovich victory will be seen as a severe blow to the leaders of the heading for a seal a victory over the Orange Revolution - Ms Tymoshenko and the outgoing president, Viktor Yushchenko. Ms Tymoshenko had refused to concede defeat.
"Sunday's vote was an impressive display of democratic elections," said the observers, headed by the Organisation for Security and Cooperation in Europe, in a statement. "For everyone in Ukraine, this election was a victory.
"It is now time for the country's political leaders to listen to the people's verdict and make sure that the transition of power is peaceful and constructive."
Success for Mr Yanukovich would mark the end of determined efforts by the pro-western Mr Yushchenko to drive Ukraine closer to the European Union and the US, and could herald a period when Kiev seeks greater balance in its relations between Moscow and the west.
The Committee of Voters of Ukraine, a domestic watchdog, said that while violations had been detected, they were unlikely to affect the overall result.
The post-poll manoeuvring began on Sunday night with Mr Yanukovich urging Ms Tymoshenko to concede defeat and step down as prime minister.
These battles could undermine Kiev's ability to manage its recession-hit economy and public finances and resume co-operation with the International Monetary Fund, which has suspended a $16.4bn rescue package.
Mr Yanukovich's recovery from his seemingly decisive defeat in 2004 owes a lot to Ukraine's east-west divide. While west Ukrainians rail that he is morally unfit for office, voters in his heartland in the industrial east never abandoned him - nor did his business oligarch backers. He exploited the vicious post-2004 splits between Mr Yushchenko and Ms Tymoshenko, which broke the Orange camp's unity and disillusioned its core supporters.
The economic crisis also hurt Ms Tymoshenko and Mr Yushchenko, who, as incumbents, bore the brunt of voters' anger.
The election followed a hard-fought campaign in which the leaders exchanged insults, corruption allegations and claims of election fraud - and spent little time on policy.
But the fact that the vote seems to have been largely fair indicates that the Orange Revolution's gains have not been entirely lost, even though voters appear to have been annoyed by the failure to cut corruption, stabilise politics or raise living standards.