Heavy-weight boxing champion and leader of the opposition Udar party Vitali Klitschko has urged Ukrainians from across the country to travel to Kyiv where, he said, Ukraine's "future is being decided."

Arseniy Yatsenyuk, head of the opposition Batkivshchyna (Fatherland) faction, said the opposition would continue to demand the resignation of Yanukovych's government, RFE/RL reports.

"The plan for tomorrow is to start with a picket in front of the Ukrainian Cabinet of Ministers. Our main political demand for tomorrow is the resignation of Ukrainian Cabinet of Ministers; a no-confidence resolution to the government has been presented to the parliament," Yatsenyuk said.

"The Party of the Regions must vote for the government that doesn't steal from people, that doesn't give orders to beat children. Our main goal is Yanukovych's resignation.  We [also] want the government of [Prime Minister Nykolay] Azarov-Yanukovych to resign."

Estimates on the crowds in Kyiv on Sunday ranged from 100,000 to 350,000. It was the largest demonstration in the Ukrainian capital since 2004 when the Orange Revolution forced the annulment of a fraud-tainted presidential election that Yanukovych had won. He later lost the re-run vote.

An estimated 40,000 were also reported to have turned out on December 1 for an anti-government rally in the western city of Lviv.