Yushchenko called on them to join mass street protests against official vote counts suggesting that pro-Russian Prime Minister Viktor Yanukovich won the presidential election.
Some 200,000 opposition supporters rallied in the center of Kyiv today in a second day of protests against the tally as announced by the Central Election Commission.
Ukraine's parliament convened in emergency session to discuss the opposition's push to have the results annulled but that opposition-led effort failed to gather a quorum. At the end of the parliamentary session, Yushchenko symbolically took an oath of office.
"I, Viktor Yushchenko, having been elected president by the will of the Ukrainian people, assuming this high post, solemnly pledge allegiance to Ukraine and swear to protect the well-being of my homeland and the Ukrainian people," Yushchenko vowed in the mock ceremony.
Opposition leader Yuliya Tymoshenko meanwhile called on supporters to march peacefully on the president's headquarters.
Kyiv's city council and the administrations of four other large cities -- Lviv, Ternopil, Vinnytsia, and Ivano-Frankivsk -- have refused to recognize the official results and have backed Yushchenko, AP reported.
(AP/AFP/Reuters)Today's related stories:"Protests Continue As Opposition Demonstrators Seek To Overturn Vote""Experts Ponder Possible Outcome Of Election Dispute"
and"Ukraine: EU Criticizes Elections"