A pro-Russian opposition party led by a former prime minister will win the most seats in Ukraine's parliamentary elections, exit polls suggest.
Support for opposition leader Viktor Yanukovych has grown
One poll put his Regions Party on 33%, ahead of President Viktor Yushchenko and his former ally Yulia Tymoshenko, but short of an overall majority.
Mr Yushchenko's Our Ukraine party was placed third, with just 13.5%.
The election is the first since the Orange Revolution brought Mr Yushchenko to power, and his appeal has waned.
The president's rivals quickly talked up their prospects ahead of official results, which are due on Monday.
Viktor Yanukovych, who was defeated in an election by Mr Yushchenko in December 2004, said his Regions party had won the election.
"Our victory will open a new page in the history of Ukraine," the Associated Press reported him saying, adding that he was willing to work with any coalition partners.
But Yulia Tymoshenko, who served as prime minister for Mr Yushchenko but was abruptly sacked last September, said a new coalition based on the alliances formed during the Orange Revolution was "practically ready".
Analysts suggested that the newly emboldened Ms Tymoshenko would expect to regain her position as prime minister in any coalition.
Voting was brisk throughout Sunday, with long queues at some polling stations and a turnout estimated at over 50%, officials said.
The Socialist party was expected to win about 5% of the vote and qualify to take seats in parliament.
Ahead of the vote, Mr Yushchenko said he hoped the Orange allies would reunite to claim a parliamentary majority.
Coalition talks will be complicated by constitutional changes that have increased parliament's powers at the expense of the president.
Following the poll, parliament - instead of the president - will choose the prime minister, and parliament also has to approve all members of the government.
Earlier the pro-Western Mr Yushchenko, who has been damaged by a weak economy and slow pace of reform, was upbeat.
The staging of democratic elections in Ukraine was itself a victory for the Orange forces, he said.
"I am in a great mood, a mood that comes before victory," he told reporters as he cast his vote with his family.
Mr Yanukovych said he supported ties with the European Union, as well as mending Ukraine's relationship with Moscow.
"Europe will support Ukraine, and Ukraine will build mutually beneficial relations with all nations, including the European Union," he said after casting his ballot.
The Orange Revolution took its name from the election campaign colour adopted by Mr Yushchenko in presidential elections held in November 2004.
Mr Yanukovych was declared the winner, but allegations of widespread vote-rigging sent hundreds of thousands of Ukrainians out on to the streets to demand change.
The election result was later overturned and Mr Yushchenko went on to win a re-run.