With riots spreading from Ukraine's capital to nearly half of the country, president Viktor Yanukovich has promised to reshuffle his government and make other concessions.
However, a prominent opposition leader said on Friday that nothing short of Yanukovich's resignation would do.
Hours after the president's comments on Friday, huge fireballs lit up the night sky in central Kiev and black smoke rose from burning tyres at giant barricades erected by protesters.
Clashes resumed at the barricades, which are just yards from lines of riot police and also made up of bags of ice and scraps of furniture.
Angry demonstrators hurled firebombs, rocks and fireworks at officers.
Riot police responded with tear-gas and several dozen protesters were rushed to a makeshift medical triage area to be treated.
Hundreds of thousands first took to the streets of Kiev after Yanukovich backed away from signing a free-trade deal with the EU, which many people saw as the key to a European future, in favour of financial aid from Ukraine's old Soviet master Russia.
The movement has since widened into broader protests against perceived misrule and corruption in the Yanukovich leadership.
Al Jazeera's Nick Spicer, reporting from Kiev on Friday, described the situation in the city as tense.
According to local news reports, Yanukovich has promised a government reshuffle, an amnesty for dozens of detained activists and changes in the anti-protest legislation.
In a meeting with religious leaders, he said that a special parliament meeting next Tuesday would push through the changes.
The dismissal of the government of Prime Minister Mykola Azarov has been one of the main demands of the opposition in two months of unrest.
Ministry building occupied
Protesters braced themselves for more clashes with the police earlier on Friday as they erected more street barricades and occupied a government ministry building in Kiev.
Yanukovich's Party of the Regions confirmed reports that two months of anti-government protests were spreading to other parts of the country, particularly the west, where it said "extremists" had seized regional administration buildings.
Vitaly Klitschko, a prominent opposition leader, said the only way out of the impasse lay with international mediation.
"Any discussion of how to settle the crisis in Ukraine must take place with the involvement of the international mediators of the highest level," a statement from his Udar party quoted him as saying.
|Ukraine's riot police accused of brutality
"Instead of shifting to solving the situation by common sense, Yanukovich has declared war on his own people. He is trying to hold on to power at the price of blood and de-stabilisation of the situation in the country. He has to be stopped."
International pressure on Yanokovich's government is mounting, with Laurent Fabius, the French foreign minister, on Friday condemning it for giving orders to open fire on demonstrators.
"I instructed the Quai d'Orsay [Foreign Ministry] to summon the Ukrainian ambassador in France today, which is a gesture to show that there is condemnation on France's part," Fabius said.
"There were orders to fire on the crowd, which is clearly unacceptable."
Martin Schaefer, a spokesman for Germany's Foreign Ministry, said his country wanted to show by summoning the Ukrainian ambassador that it was "serious" with its criticism.
"We hope and assume that the government and the opposition have recognised that violence is senseless and that any new escalation with more casualties will not bring about anything good for Ukraine," Schaefer said.
So far the EU's 28 members have not been able to agree on whether to threaten Ukraine with sanctions, as the US has done.
But Schaefer said Germany was not "excluding the possibility that the time will come when the question of sanctions will come up".