Yanukovych filed several complaints about the poll with the Central Election Commission, alleging mass fraud. The commission threw out his appeal last week.
Earlier, the new head of the Organization for Security and Cooperation in Europe, Slovenian Foreign Minister Dimitrij Rupel, praised Ukraine's new democracy, saying that a democratic Ukraine is important for European stability.
Rupel spoke in Kyiv after meeting with Ukrainian Foreign Minister Kostyantyn Hryshchenko at the end of a two-day visit. It was Rupel's first foreign trip since Slovenia assumed the rotating one-year OSCE chairmanship on 1 January.
For more RFE/RL coverage and analysis of the political crisis in Ukraine, click here.