The European Union is stepping up diplomatic efforts to mediate the presidential election dispute in Ukraine.
EU foreign policy chief Javier Solana and Polish President Aleksander Kwasniewski will meet in Kiev Friday with the principal figures in the standoff.
On Thursday, Ukraine's Supreme Court barred publication of the results of Sunday's presidential election until it considers charges by opposition candidate Viktor Yushchenko of widespread voter fraud. The court set Monday for hearings.
The ruling prevents Prime Minister Viktor Yanukovych from being inaugurated as president. Electoral officials say he won the vote by a slim margin.
International observers say the election was seriously flawed.
Friday, opposition supporters blockaded the Cabinet building where Mr. Yanukovych works and refused to let staff enter.
Some information for this report provided by AP and AFP.