Vitali Klitschko, leader of Ukraine's UDAR party, has called for early presidential and parliamentary elections in Ukraine.

"We are confident that we can pressure the current administration together to call early presidential and parliamentary elections," he told an opposition rally held in Kyiv on Sunday.

Klitschko said he is confident that the opposition forces can "unite and deliver a blow, which will be decisive."

"There will be no victory without a fight," he said.

Klitschko said the UDAR, Batkivschyna, and Svoboda parties have different ideologies. "However, we have one thing in common: we want to live in a democratic country," the politician said.

Oleh Tiahnybok, leader of the Svoboda faction, has called on the people of Ukraine to support the opposition.

"We are asking for your support, your energy […] We are in the parliament, you are in the streets of the capital and the cities and villages of Ukraine," Tiahnybok said at a protest rally held in Kyiv on Sunday.

Tiahnybok promised that all steps and decisions made by the opposition forces will be discussed with the people of Ukraine.

Mykola Tomenko, chairman of the parliamentary committee on freedom of speech and information issues, called on the opposition to hold an alternative national referendum.

"I think we should agree and act as follows: if Yanukovych wants to hold his referendum, we should raise the question of organizing a simultaneous 'national referendum,'" Tomenko told an opposition protest in Kyiv.

If Yanukovych wants to raise the question about stripping some parliamentarians of their parliamentary immunity, the "national referendum" should address the issue of stripping the Ukrainian president, judges and parliamentarians of immunity, he said.

"If we raise the question of introducing a majority system of parliamentarians' elections, the national referendum should address the issue of introducing a party system of elections with open lists. In addition, the national referendum should address the issue of liquidation of regional, district, and local state administrations," Tomenko said.

"Our goal is Yanukovych's resignation and a new president of Ukraine," Arseniy Yatseniuk, leader of the Batkivschyna parliamentary faction, told an opposition protest in Kyiv.

Yatseniuk reiterated that opposition activists are well aware that Yanukovych will not resign in one month.