Ukrainian Prime Minister Yulia Tymoshenko urged a court Friday to examine carefully all the evidence regarding Ukraine's run-off presidential election, which she says was rigged.
A court in Kyiv began hearing the prime minister's appeal to block the inauguration later this month of her rival, Viktor Yanukovych.
Ms. Tymoshenko said she would accept the court's decision if all the evidence regarding the February 7 vote is studied thoroughly.
Yanukovych is due to be sworn in February 25 after beating Prime Minister Tymoshenko by more than 3.5 percentage points.
She says massive election fraud puts in question one million votes and could have affected the outcome.
European election monitors have said that Ukraine's presidential election was generally free and fair.
The court has put the election results on hold until it rules.
Yanukovych's supporters call the court's decision a routine procedure, and say the inauguration will go on as scheduled.
Mr. Yanukovych has resigned his post in parliament ahead of the inauguration.
Tymoshenko says she delivered a box of documented evidence to Kiev's Higher Administrative Court that she says will prove the vote was rigged.
Ms. Tymoshenko was one of the main leaders of Ukraine's massive 2004 protests, following a presidential election which initially showed Yanukovych as the winner. The huge protests over alleged election fraud led to a new vote, won by Viktor Yushchenko.
Some information for this report was provided by AFP, AP and Reuters.