KIEV (AFP) - Ukrainian President Viktor Yanukovych on Saturday held a new round of crisis talks with opposition leaders as fears grew of an impending crackdown on thousands of protesters locked in a standoff with police in Kiev.

The Ukrainian interior minister warned that efforts to solve the country's deadly crisis without using force were proving "futile" as the opposition accused Mr Yanukovych of planning to impose a state of emergency.

The European Union urged concrete steps to end the crisis, which has raised fears of a prolonged civil conflict and according to officials has already left three dead.

The authorities also faced mounting pressure outside Kiev with protesters storming regional administration offices not just in the anti-Yanukovych west of the country but also north and east of Kiev.

With tensions rising in the capital after a night of sporadic clashes between security forces and protesters, Interior Minister Vitaliy Zakharchenko bluntly warned that the use of force was a possibility.

"The events of the last days in the Ukrainian capital have shown that our attempts to solve the conflict peacefully, without recourse to a confrontation of force, remain futile," he said in a statement.

Accusing the mainstream opposition of failing to control radicals, Mr Zakharchenko said the authorities now had information that the protesters were "hoarding firearms" at their headquarters.

He later said that all protesters remaining on Independence Square and occupying official buildings in Kiev would be considered as "extremist groups" and the authorities would use force if need be.

In a possible last-ditch attempt to find a peaceful solution, Mr Yanukovych held unscheduled talks with the opposition.

The presidency said he was meeting with UDAR (Punch) party leader and world boxing champion Vitali Klitschko, Fatherland party leader Arseniy Yatsenyuk and nationalist Svoboda (Freedom) party leader Oleg Tyagnybok at the presidential administration.

In a sign of a possible split within the ruling Regions Party over how to deal with the crisis, Ukraine's richest man Rinat Akhmetov said that dialogue was the only way forward.

"There can be only one solution to the political crisis - a peaceful one. Any use of force is unacceptable," said Mr Akhmetov, an ally of Mr Yanukovych and bankroller of his party. "The only way out is to move from street confrontation to negotiations," he added in a statement released by his SCM holding company.

Mr Yatsenyuk's Fatherland party said in a statement on its website that it had information that the decree on the emergency situation was ready to be signed by the president and the authorities were preparing to disperse protesters.

The epicentre of the crisis - Ukraine's worst since its independence in 1991 - was relatively calm early Saturday but hundreds of protesters were still at the scene with the security forces on the other side of their lines.

A Ukrainian protester who was severely hurt in clashes with riot police died in hospital, Kiev officials said on Saturday. The opposition said the man, named as was Roman Senyk, 45, had died of gunshot wounds.

The clashes have now killed six activists, according to protesters. The authorities have confirmed three shooting deaths but insisted police were not involved.

The protests first erupted in response to Mr Yanukovych's refusal to sign a key deal with the European Union in November. But they have snowballed into anti-government protests against Mr Yanukovych's four-year rule, which the opposition claims has been riddled with corruption and nepotism.

Demonstrators were on Saturday still occupying regional adminstration buildings in Lviv and other regions across the pro-EU west of Ukraine in a major blow to Mr Yanukovych.

Protesters were also seeking to seize buildings in regions north and east of the capital Kiev, signalling that the protest mood was spreading across the country.

In a conciliatory gesture, Mr Yanukovych said on Friday that an extraordinary parliament session on Tuesday will "take a decision about reshuffling the government". He also said that Parliament would discuss changes to tough anti-protest laws passed last week, which reinvigorated the protest movement, and that those detained in rallies who are "not guilty of heavy crimes" will be amnestied.

But the protesters packing Independence Square in Kiev have responded to the concessions with derision, calling instead for Mr Yanukovych to resign.

World leaders have condemned the violence and urged the president to hold talks. But so far Western pressure has had little impact on the standoff.

EU Enlargement Commissioner, Stefan Fuele, who held talks with Mr Yanukovych in Kiev on Friday, urged the Ukrainian government to take concrete steps to halt "a spiral of violence and intimidation" and restore peace in the country.

"I have discussed a series of steps to this end, that could lead to confidence building and to a political process aimed at ending this crisis," he added.

EU foreign policy chief Catherine Ashton is due in Kiev next week while the crisis is also expected to dominate an upcoming EU-Russia summit.

Poland's Prime Minister Donald Tusk has starkly warned of a "black scenario that is really possible: Ukraine falling apart".