Violence has continued in the Ukrainian capital Kiev, after President Viktor Yanukovych promised to make concessions to try to end the country's crisis.
As dawn broke on Saturday, fires still burned in the city centre. Overnight, protesters threw rocks and petrol bombs at police, who responded with tear gas.
Mr Yanukovych pledged to amend anti-protest laws and reshuffle the cabinet.
But opposition leader Vitaly Klitschko said the protesters now wanted the president to resign.
On Friday night, protesters burned tyres on barricades on Hrushevskyy Street - the scene of recent deadly clashes near the main protest camp on the capital's Independence Square.
Fireballs lit up the sky. Witnesses said several arrests were made.
Activists seized a number of government offices across Ukraine.
The crisis escalated this week with the first deaths since the unrest started two months ago. Two protesters were shot dead during clashes on Hrushevskyy Street.
The opposition says they were killed by riot police or snipers - the government denies the claim.
And an activist was found dead in woods near Kiev after apparently being abducted, tortured and left to die in the snow.
The demonstrations were initially triggered by the last-minute decision of Mr Yanukovych's government to ditch a proposed association and free trade deal with the EU in November - under heavy pressure from neighbouring Russia.
But the protests later widened their demand to include the fight against what activists say are widespread government corruption and abuse of power.
The authorities deny the allegations.
'All legal means'
At a meeting with religious leaders in Kiev on Friday, Mr Yanukovych pledged to change the anti-protests laws rushed through parliament last week and reshuffle the government at an urgent session of parliament due to begin on Tuesday.
And he said an amnesty would be granted to those detained activists who had not committed "grave crimes".
But Mr Yanukovych vowed to use "all legal means" if a solution to the crisis were not found.
He also said that those officials linked with the use of force against the protesters would be sacked.
Speaking shortly after the meeting, Mr Klitschko, a former heavyweight world champion, said the offer had come too late.
"People are demanding the resignation of the president," he was quoted as saying by the Interfax-Ukraine news agency.
Talks between the opposition and the president have stalled. On Thursday night, protesters in Kiev's Independence Square - widely known as Maidan - voted to stop any further talks, and the decision was taken to expand the main protest camp.
State of emergency call
On Friday anti-government demonstrators spread beyond Kiev.
In the western city of Ivano-Frankivsk, some 1,500 protesters occupied the regional administration and barricaded themselves in the building. They are now demanding that the local governor should resign immediately.
In Chernivsti, also in the west, crowds stormed the governor's office as police tried to protect the building. People shouted "Shame on you!" and "Resign!"
In Lutsk, in the north-west, a big demonstration was being held outside the local administration.
Regional offices were being blockaded in the western city of Uzhgorod and unrest was reported in the eastern city of Sumy.
Meanwhile, in Lviv, protesters have built barricades around the governor's office that they seized on Thursday. There were also reports that some members of the special police, Berkut, were resigning.
Separately, the parliament of the Crimean Autonomous Republic - seen as a staunch supporter of Mr Yanukovych - urged the president to declare a state of emergency.