Yushchenko also appealed to Yanukovych, who leads a pro-Russian majority coalition in parliament, not to "stir up the population".
Several thousand anti-Yushenko protesters have taken to the streets of Kiev in support of the parliament and on Thursday they were addressed by MPs. Constitutional court ruling
Yanukovich has said that Ukraine should wait for a ruling from the constitutional court on whether the president's dissolution of parliament was legal.
|"Today steps are being taken in preparation for the snap election. |
This is illegal"
Viktor Yanukovich, Ukrainian prime minister
A ruling is expected to take more than a month.
"The only way out is to wait for the constitutional court's decision. Today steps are being taken in preparation for the snap election. This is illegal," he said.
The European Union has intervened in the standoff for the first time.
Javier Solana, the EU foreign policy chief, telephoned the main protagonists to appeal for them to find a political solution and exercise restraint, his spokeswoman said.
"Solana telephoned Yushchenko on Tuesday night and called Yanukovich and [opposition leader Yulia] Tymoshenko yesterday to urge calm and restraint and efforts to go back to dialogue," Cristina Gallach, his spokeswoman, said.
"We need a solution that respects the democratic rights of the people."
Yushchenko became president after the "Orange Revolution" in 2004, pledging to modernise the economy and move the country closer to the West and eventual European Union membership.
But there has been growing discontentment in the former Soviet state as the pace of change has slowed and the political crisis has grown.