Ukraine's Prime Minister says he will take part in a new runoff presidential election after the supreme court ruled the results of a previous poll were invalid. Parliament is holding a special Saturday session to discuss what comes next, as electoral officials begin planning for the new vote later this month.
Ukrainian Prime Minister Viktor Yanukovych says he has "no choice" but to run in the new election despite feeling that the court's decision violates Ukraine's constitution.
In a statement, Mr. Yanukovych said the court acted "under pressure from the street", a reference to the tens of thousands of opposition supporters who filled the center of Ukraine's capital Kiev for almost two weeks.
A party atmosphere prevailed among those supporters after they learned of the court's decision.
At one point, opposition leader Viktor Yushchenko told the crowd the decision was "their victory" and asked them to stay in place for the time being as the next steps are worked out.
He called on the government to replace the electoral commission that had given victory to Mr. Yanukovych.
The European Union and other Western countries have welcomed the court's ruling and offered to assist in preparing for the repeat runoff election, which is likely to be held on December 26.
EU officials are now studying ways they can help, as foreign monitors prepare to again come to observe an electoral process that will come under more scrutiny than ever. EU Foreign Policy chief Javier Solana urged all parties in Ukraine to respect the ruling.
Yet while the mood in Kiev was jubilant, a very different atmosphere prevailed in eastern regions which strongly support Mr. Yanukovych.
Aides to Mr. Yanukovych called the court ruling a "political decision" because the judges went beyond ruling on the validity of the election results and ordered a brand new vote.
The court's decision was also a big setback for current President Leonid Kuchma and Russian President Vladimir Putin, who openly backed Mr. Yanukovych and repeatedly criticized the West for "interfering" in Ukraine.
Just a day before the court decision, the two presidents met in Moscow and voiced strong opposition to holding a new runoff vote, arguing that a brand new election involving other candidates was necessary .
On Friday, the Russian parliament passed a resolution accusing the West of taking "destructive actions" in Ukraine by "pushing a radicalized portion of Ukraine's population towards dangerous actions."
The Russian Foreign Ministry also accused Europe of interfering in Ukraine's internal affairs and supporting a "breach" of the country's constitution.
Russians have watched with dismay as events have unfolded in a country that was ruled by Moscow for over three centuries and which the Kremlin views as lying entirely within its sphere of influence.