The European Union is calling on Ukraine to delay announcing the results of Sunday's contested election until after an independent review.
A European Commission spokesman said Wednesday that there could be serious consequences for E.U. - Ukraine relations if a serious review of the voting is not carried out.
Officials say the election results may be announced today. Thousands of opposition supporters are continuing their protests on the streets of the capital, Kiev, for a third day.
Ukraine's opposition leaders say they are willing to hold talks with President Leonid Kuchma, but only to discuss the peaceful transition of power to challenger Viktor Yushchenko.
Official but incomplete results show pro-Russian Prime Minister Viktor Yanukovich winning the vote. However, opposition supporters and U.S. and European observers report indications of extensive voter fraud.
Information for this report is provided by AP, AFP and Reuters.