Thousands of supporters of Ukraine’s Russian-leaning prime minister marched Wednesday to the office of the pro-Western president, protesting a presidential order to hold early elections.

President Viktor Yushchenko on Monday night ordered parliament dissolved, and he called new elections for May 27, plunging Ukraine into its most serious political crisis since the 2004 Orange Revolution.

Prime Minister Viktor Yanukovych has called the decision illegal and appealed to the 18-judge Constitutional Court.

“Until the issue is considered by the Constitutional Court, we will not prepare for elections in any way,” the prime minister said Wednesday.

Yanukovych’s supporters have taken over the main Independence Square in downtown Kiev. Elderly people wearing red scarves in support of Yanukovych’s coalition partner, the Communists, danced, while younger supporters sat on the edge of fountains or the ground.

“We will be victorious because the law is on our side,” said Halina Gusova, 59, a Communist supporter. “And after we win this, our next goal will be to remove the president.”