By Richard Balmforth and Pavel Polityuk
KIEV (Reuters) - Ukrainian President Viktor Yanukovich called for an emergency session of parliament to end the country's political crisis and violent unrest, in a sign he might be ready to soften his hardline stance and strike a compromise.
Opposition leaders who held discussions with Yanukovich that ended late on Thursday immediately went to meet protesters manning street barricades to give their account of the talks.
It was not immediately clear what, if any, concessions had been made. But an Ekspreso TV station correspondent reported that boxer-turned-politician Vitaly Klitschko urged activists to stick to a truce agreed earlier on Thursday until Friday morning.
Klitschko, who was accompanied by nationalist leader Oleh Tyahnibok, was reported to have said that Yanukovich had promised to release all those who had been detained by police in the present unrest.
A third opposition leader in the talks, former economy minister Arseny Yatsenyuk, said he felt that bloodshed had been averted, according to Russia's Interfax news agency. But he also gave no real details.
Three people on the protesters' side were killed early on Wednesday - two of them from gunshot wounds - as tensions grew on the streets of Kiev after two months of unrest against Yanukovich's rule. More than 150 police have been injured.
Yanukovich's offer of a special parliamentary session to help settle the crisis appeared to offer the first glimmer of a chance the crisis could be resolved. The parliamentary website said the session would be held next Tuesday.
Underlining the level of mistrust between the government and opposition, Prime Minister Mykola Azarov accused protesters of trying to stage a coup d'etat, and dismissed the possibility of an early presidential election to resolve the standoff.
"All those who support this coup should say clearly, 'Yes, we are for the overthrow of the legitimate authorities in Ukraine', and not hide behind peaceful protesters," Azarov said at the World Economic Forum in Davos, Switzerland.
"A genuine attempt at a coup d'etat is being carried out," Russian news agency Interfax quoted him as saying.
Azarov told Reuters the government had no plans to introduce a state of emergency: "We don't see the need for tough and extreme measures at the moment ... But don't put the government into an impasse," he said.
"People should not think that the government lacks available resources to put an end to this. It is our constitutional right and obligation to restore order in the country."
The protests against Yanukovich began in November, when he pulled out of signing a free trade deal with the European Union in favor of closer economic ties with former Soviet overlord Russia.
The unrest has swollen in recent weeks, and turned violent on Sunday when hard-core radicals broke away from the main protest area in the capital Kiev and clashed violently with riot police.
Outside the capital, thousands stormed the regional administration headquarters in Rivne in western Ukraine on Thursday, breaking down doors and demanding the release of people detained in the unrest there, UNIAN news agency reported.
In the central Ukrainian town of Cherkasy, 200 km (125 miles) south of Kiev, about 1,000 protesters took over the first two floors of the main administration building and lit fires outside the building.
In calling the emergency session, Yanukovich told parliamentary speaker Volodymyr Rybak that the "situation must be settled immediately".
Rybak said the proposed emergency session of parliament could consider the opposition's call for Azarov's government to step down.
He added that "questions linked to laws passed by parliament" could be discussed - apparently a reference to sweeping anti-protest laws rammed through parliament last week by Yanukovich loyalists.
Those laws served to boost mass demonstrations on the streets of Kiev at the weekend, and the opposition is demanding they be repealed.
The turmoil has caused alarm abroad.
U.S. Vice President Joe Biden phoned Yanukovich on Thursday and warned him that failing to de-escalate the standoff could have "consequences," the White House said.
"The Vice President underscored that only the government of Ukraine can ensure a peaceful end to the crisis and further bloodshed would have consequences for Ukraine's relationship with the United States," the White House said.
German Chancellor Angela Merkel expressed anger over the crackdown.
"We are greatly worried, and not only worried, but also outraged at the way laws have been pushed through that call these freedoms into question," she told a news conference.
But Merkel added it would be wrong for Europe to respond to the violence with sanctions at this stage.
French President Francois Hollande called on Ukrainian authorities to "rapidly seek dialogue".
A European Commission spokesman said Yanukovich had spoken to President Jose Manuel Barroso on Thursday and assured him he was ready to maintain dialogue and saw no need to impose a state of emergency in Ukraine.
Former Soviet leader Mikhail Gorbachev urged the presidents of Russia and the United States to help broker negotiations, and said Ukraine was facing a possible "catastrophe".
(Additional reporting by Natalia Zinets; Editing by Sonya Hepinstall)