(RFE/RL) -- Ukraine's Central Election Commission has officially declared Viktor Yanukovych the winner of the presidential election held on February 7, but Prime Minister Yulia Tymoshenko is claiming fraud and has pledged to take the case to court.



The election commission today confirmed the results that showed Yanukovych beating Tymoshenko by a 3.48 percent margin, or some 888,000 votes. The announcement comes three days ahead of the deadline for releasing the final official results of the vote.



The announcement came after Tymoshenko said she plans to challenge the official result in court in a televised statement late on February 13.



"Today I can firmly tell you that Ukraine's elections were falsified, and this is not a political declaration but a clear legal assessment by lawyers," Tymoshenko said.



Tymoshenko's supporters are now expected to lodge an official appeal against the results and present evidence of fraud to a Kyiv high court. Reports say the court is expected to take several days to consider the evidence presented.



The prime minister claimed more than 1 million votes had been falsified or miscounted, and she named the Crimean peninsula -- a Yanukovych stronghold -- as the site of "shocking" irregularities.



International monitors described the election as “an impressive display of democracy.” The European Union, the United States, and NATO leaders have congratulated Yanukovych.



But Tymoshenko said Yanukovych “will never become the legitimately elected president of Ukraine."



However, she pledged not to call out her supporters for mass protests like those of the 2004 Orange Revolution.



"Not taking this to court will mean giving up Ukraine to criminals without a fight,” Tymoshenko said. “Ukraine needs stability and calm as never before. That's why we'll be acting only in a legal manner, and only in court. I want to state clearly -- Yanukovych is not our president."



Yanukovych was pronounced the victor six years ago, only for the result to be overruled because of vote-rigging. The Orange Revolution eventually brought Tymoshenko's former ally, President Viktor Yushchenko, to power.



Tymoshenko also claimed in her appeal that several observers from the Organization for Cooperation and Security in Europe (OSCE) had agreed to support her legal challenge with "video evidence" in courts.



Officially, however, the OSCE has declared the elections "professional, transparent, and honest" in a joint statement with other international observers.



Responding to Tymoshenko, the deputy chairwoman of Yanukovych's Party of Regions said that any legal challenge from Tymoshenko has no hope of success.



Speaking to the Associated Press, Anna German accused Tymoshenko of wanting to win concessions from Yanukovych in negotiations, and said Yanukovych's party would not negotiate about democracy.



On February 10, Yanukovych demanded his rival abandon her protests and resign as prime minister, saying the country “does not need a new crisis."



Ukraine has been in political deadlock for several years, undermining its ability to deal with a severe economic crisis.



With agency reports.