Ukrainian President Viktor Yanukovich has been holding new and previously unannounced talks with opposition leaders aimed at solving the crisis in the country, the presidency has said.
Along with senior aides, Yanukovich was meeting 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, it said.
The crisis talks come hours after the interior minister warned that efforts to solve the country's deadly crisis without using force were "futile" as protesters and police were locked in a tense standoff in the capital, Kiev.
|Ukraine leader's offer fails to end protests
"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," Vitaliy Zakharchenko said in a statement.
Accusing the mainstream opposition of failing to control radicals, Zakharchenko said the police would from now on consider all protesters on Independence Square and those occupying official buildings in central Kiev as extremist groups.
On Saturday, the head of Ukraine's police said protesters had released two officers they seized and tortured, but a protest leader called the claim a provocation aimed at justifying a crackdown.
Overnight, demonstrators had hurled Molotov cocktails at police who responded with stun grenades and rubber bullets, AFP correspondents said.
Hundreds poured into the protest zone on Saturday morning, with reports of the main energy ministry building in central Kiev being besieged and the protest spreading beyond the capital.
According to Energy Minister Eduard Stavytsky, about 100 protesers attempted to seize control of his ministry. "I went to them and said that if they did not peacefully leave the building then the whole energy system of Ukraine could collapse," said Stavytsky.
He said protesters had left the building but he had been told they were blocking entry to the building outside.
A regional administration building in Vinnitsya, about 180km southwest of Kiev was also seized by the protesters, news reports said.
Concessions to protesters
The siege comes a day after President Viktor Yanukovich offered concessions to protesters, including changes in government ministers and amendments to the anti-protest laws passed through parliament last week.
But renewed activity on the streets of the capital, and the spread of protests to the provinces, appear to confirm a popular rejection of his terms.
Reporting from Kiev, Al Jazeera's Nick Spicer noted that the central government "has not just been losing ground, it has been losing people. A good part of the presidential press service has resigned".
"What the president has suggested is a cabinet reshuffle, and the prime minister has called the Swiss president to mediate," said Spicer.
The European Union urged concrete steps to end the crisis, which according to activists has already left six dead and risks spiralling into another bloody confrontation if President Yanukovich chooses to use force to end the well fortified two-months protest camp in the capital.
But 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 talks could be the only solution.
"There can be only one solution to the political crisis - a peaceful one. Any use of force is unacceptable," said Akhmetov, an ally of Yanukovich.