Ukrainian lawmakers failed to agree on curbing the president's powers at a stormy debate on Tuesday as international pressure grew for ending the two-month crisis with the expected arrival of the EU foreign policy chief.

Catherine Ashton is due to meet opposition leaders for dinner in Kiev on Tuesday and President Viktor Yanukovych on Wednesday to discuss plans for financial aid from Brussels and Washington in exchange for democratic reforms.

Ukraine's protests erupted in November after Yanukovych rejected a key EU pact in favour of closer ties with Moscow, and the turmoil has now become an all-out movement to oust him.

Demands of pro-EU protest leaders include constitutional amendments that would cut presidential powers and freedom for arrested activists without conditions, but Yanukovych's ruling Regions Party has insisted this can only happen if occupied government buildings are vacated.

An anti-government protester takes part in a rally in front of a district administration building where Kiev's city council is sitting in Kiev on February 4, 2014 Genya Savilov, AFP

In a sign that Yanukovych's position is softening further, his personal representative in parliament Yuriy Miroshnychenko, told AFP that the president was considering "two possible scenarios".

"The first is the release of occupied buildings and an amnesty and the second is early elections. The amnesty is not working out," he said, referring to the release of those arrested in past weeks.

A conditional amnesty came into force on Saturday and gives protesters 15 days to leave the buildings but the opposition has dismissed the law, saying it turns activists into "hostages".

Protesters camped out on Kiev's Independence Square -- the hub of a movement that has spread across Ukraine -- expressed mixed feelings about the possibility of Yanukovych stepping down before the end of his mandate in 2015.

"Until we see a complete change which is not just Yanukovych, people will stand here," said Vasyl, a campaigner from Lviv in western Ukraine.

Bogdan, an activist from Kiev, said: "It would be the best way for us. A full reset of power. Both president and parliament."

A woman shouts slogans while watching a parliament session on a video wall at Kiev's Independence square on February 4, 2014 Aris Messinis, AFP

At a pro-government camp just a stone's throw away from the protesters, 27-year-old Andriy Kucher said Yanukovych's resignation would mean that "the military coup has been successful".

"He was democratically elected," Kucher said.

'End to dictatorship'

An anti-government protester is reflected on piece of mirror near a road block in Kiev on February 3, 2104 Angelos Tzortzinis, AFP

In parliament, world champion boxer turned protest leader Vitali Klitschko called for an "end to the dictatorship" saying Ukrainians were fed up with corruption and lawlessness.

After meeting Yanukovych on Tuesday, Klitschko said he had pressed him on the need for a constitutional reform to reduce presidential powers and give more clout to the legislature.

"He told me it would take between one and six months. I told him we don't have time," he said.

Anti-government protesters stand in front of a line of riot police in Kiev on February 3, 2104 Angelos Tzortzinis, AFP

Klitschko said it would be possible to speed up the process by reverting to a previous version of the constitution with a parliamentary vote and the session was adjourned to Wednesday.

Another opponent, nationalist Oleg Tyagnybok, called for "de-Putinisation" -- a reference to Russian President Vladimir Putin, saying: "The Kremlin is trying to break up Ukraine".

The crisis has sparked tensions between the West, which is considering sanctions against Ukrainian officials, and Russia, which has accused the EU and US of interference in the former Soviet republic.

Opposition MPs chanted "Killers! Killers! Killers!" as the chief lawmaker from the Regions Party, Oleksandr Yefremov, took the floor with an emotional speech in which he blasted the "extremism" of the protesters.

Yanukovych has scrapped draconian anti-protest laws and the prime minister and the entire cabinet have resigned under opposition pressure but other demands remain unanswered.

At least two protesters and two policemen have been killed in clashes and the opposition says activists are being beaten by pro-government militias as part of a "secret repression".

The violence has increased pressure from the international community for a swift solution.

Opposition leader Arseniy Yatsenyuk has asked for a "Marshall Plan" -- a reference to the massive US aid give to Europe after World War II to rebuild and prevent the spread of Communism.

Yatsenyuk said the minimum required would be the $15 billion (11 billion euros) that Russia has promised Ukraine in a critical bailout that is now on hold pending a resolution of the crisis.

But European Commission president Jose Manuel Barroso said on Monday there would be "no bidding competition" with Russia, and EU diplomats hinted the amount would be much lower.