KIEV - Ukrainian Prime Minister Yulia Tymoshenko declared on Saturday that she had proof of cheating in a Feb. 7 presidential election by her rival Viktor Yanukovich which she would take to court to contest his victory. In her first real public appearance since Sunday's poll, the charismatic 49-year-old Tymoshenko said: "I want to clearly state: Yanukovich is not our president. Whatever happens in future, he will never become the legitimately elected president of Ukraine." But, in a televised broadcast to the nation, she promised not to call people out in mass street protests like those of the 2004 Orange Revolution, when she helped lead a successful challenge to his election and had it overturned as fraudulent. "I will not call another 'Maidan' (Independence Square demonstration) and will not allow public protests," she said. Tymoshenko, who looked resolute and wore her trademark peasant hair braid, said that more than one million votes which would have handed her victory had been subject to fraud. According to preliminary official figures, Yanukovich beat her by 3.5 percentage points with about 880,000 more votes. "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," said Tymoshenko. "With all this proof, I have taken the only possible decision: to challenge the results of the election in court. I will defend our state and the choice we made on the basis of legal documents," she said. "Not going to court would mean giving up Ukraine to criminals without a fight." Tymoshenko's stubborn refusal to concede to Yanukovich flies in the face of the West's endorsement of the official result. US President Barack Obama on Friday led world leaders, the European Union and NATO in congratulating him on his victory. Yanukovich, a 59-year-old ex-mechanic from the Donbass mining region, is expected to tilt Ukraine back towards Russia, its former imperial master, after five years of estrangement under pro-Western President Viktor Yushchenko. Yanukovich, in an interview aired earlier on Saturday by Russian television, said Ukraine may allow Russia to station its Black Sea Fleet in the port of Sevastopol beyond a scheduled withdrawal in 2017.