Kiev, Ukraine ? Supporters of opposition leader Viktor Yushchenko lost a round to their foes in parliament Saturday, when pro-government lawmakers helped block legal changes intended to prevent fraud in the Dec. 26 repeat of the country’s presidential runoff vote.

Buoyed by a momentous Supreme Court ruling a day earlier that ordered the new vote, Yushchenko’s supporters vowed to force parliament to adopt the legislation by continuing their marathon protest in Kiev’s central square.

Outgoing President Leonid Kuchma tried to bring European pressure on the opposition, which he accused of reneging on its promises. Kuchma called for a new round of European-mediated talks with the opposition on Monday.

The jockeying for position came as the opposition celebrated its court victory, confident Yushchenko can beat Prime Minster Viktor Yanukovych if a fair runoff is held. Yanukovych, Kuchma’s ally, confirmed he would compete in the new vote, and the Central Election Commission formally set a Dec. 26 date for the balloting, as ordered by the court.

Yushchenko had been hoping for quick approval of a raft of bills that would amend election laws and reshuffle the election commission, which the opposition accused of covering up fraud in the initial runoff Nov. 21. The opposition says the changes are needed to ensure the new vote is fair.

But the package was blocked when a compromise agreement fell apart, and the parliament adjourned for 10 days without passing the legislation.

Supporters of Ukrainian opposition leader Viktor Yushchenko celebrate at a rally in the main square of Kiev. Buoyed by Friday's momentous Supreme Court ruling that canceled the fraud-tainted Nov. 21 runoff, Yushchenko supporters again rallied in the streets Saturday, but parliament declined to enact election reforms that the opposition had pushed for.