A Ukrainian court has suspended the country's official presidential election results after agreeing to consider an appeal from Yulia Tymoshenko, the prime minister.
It comes after Tymoshenko refused to concede defeat to Viktor Yanukovych, who was shown to have won the vote by a narrow 3.5 per cent, and accused his party of election fraud.
Ukraine's administrative court said on Wednesday that it would rule on her challenge to the results by February 25, the date politicians had planned to inaugurate Yanukovych.
"The supreme administrative court of Ukraine ... has put on hold the decision of the central election commission declaring the results of the second round of Ukraine's presidential elections and the election of Viktor Yanukovych as president," it said in a statement.
Anna German, the vice chairwoman of Yanukovych's Party of Regions, said the court deliberations were a "mere formality".
"These proceedings can't overturn the obvious: The majority of Ukrainians have voted for Yanukovych," she said.
"The entire world has recognised Yanukovych's victory."
Viktor Nebozhenko, the head of the Ukrainian Barometer polling agency, said Tymoshenko has "little chance of winning" the court appeal.
"Tymoshenko's key goal is now to stay in the prime minister's seat. She has nothing to lose and is ready to offer promises and jobs."
Tymoshenko has urged a full recount of the vote, and delivered what she said was evidence to the court on Tuesday.
But she has asked her supporters not to hold street demonstrations as they did in what became known as the 2004 Orange Revolution.
Those protests lead to a court's overturning Yanukovych's presidential election victory that year and ordering a rerun, which was won by Tymoshenko ally Viktor Yushchenko.
International observers have deemed Ukraine's latest election free and fair, and many world leaders, including Barack Obama, the US president, have already congratulated Yanukovych.