The EU has agreed to impose sanctions on Ukrainian officials "responsible for violence and excessive force" after the bloodiest day of clashes in Kiev.
In a statement, EU foreign ministers said targeted sanctions including asset freezes and visa bans would be introduced "as a matter of urgency".
Dozens of anti-government protesters died in Kiev on Thursday. Many were reportedly killed by snipers.
In all, 75 people - including policemen - have been killed since Tuesday.
In addition to those, Ukraine's health ministry also said that 571 were injured during three days of violence in the Ukrainian capital.
Protesters had captured 67 police, the interior ministry said. A number of them were later released by activists on the main protest camp in Independence Square - widely known as the Maidan.
The tense stand-off is continuing overnight, with the activists standing guard on the Maidan barricades for possible new police attacks.
"No circumstances can justify the repression we are currently witnessing," the statement from EU foreign ministers said on Thursday.
EU foreign policy chief Catherine Ashton said the "prime responsibility" to get talks between the two sides under way lay with President Viktor Yanukovych.
Speaking after an emergency meeting of EU foreign minsters in Brussels, she said ministers had expressed their "dismay" at the latest violence and had agreed to "suspend export licences for equipment for internal repression".
Implementation of the measures "will be taken forward in light of developments in Ukraine", she added.
The EU had until now refrained from imposing sanctions, preferring to emphasise dialogue and compromise.
The US state department had already announced visa bans on 20 members of the Ukrainian government but has not provided any names.
Late on Thursday, Vice President Joe Biden warned President Yanukovych in a telephone conversation that Washington was ready to impose sanctions against Ukrainian officials guilty of ordering troops to fire on protesters.
Dozens of protesters were killed by security forces in Kiev on Thursday following the breakdown of a truce the previous day.
Activists and Maidan medics suggested the death toll could be as high as 100 and would rise further.
A number of dead bodies of protesters killed on Thursday were brought to Independence Square, the focal point of the protests, the BBC's Duncan Crawford in Kiev reports.
Assembled crowds shouted "Martyrs!" and "Heroes!", with some protesters in tears, our correspondent adds.
Witnesses have told the BBC that some of those killed on Thursday died as a result of single gunshot wounds, typical of sniper fire.
Video footage has emerged apparently showing snipers firing on demonstrators who had been trying to retake their protest camp in Independence Square.
The authorities said that one policeman had died, however an activist reported that as many 10 police officers had been killed.
Officials said more than 20 policemen had also been injured.
Witnesses reported live rounds, petrol bombs and water cannon being used at Independence Square during Thursday morning's clashes.
Some armed demonstrators were also reported to be firing towards security forces.
Gunshots pierced the windows of rooms at the Ukraina Hotel, which is serving as the base for all foreign media in Kiev, including the BBC.
Earlier, several dozen protesters were using the lobby as a triage centre for the wounded, and a priest arrived, says the BBC's Kevin Bishop, at the scene.
Protesters - some of them armed - asked hotel guests for blankets to use as bandages.
A statement on the presidential website blamed the opposition for starting the violence, saying the "calls for a truce and dialogue were nothing but a way of playing for time to mobilise and arm militants from Maidan".
MPs assembled for a session of parliament on Thursday afternoon voted to condemn the recent violence.
They also called for the use of weapons against protesters to be banned, and for troops and police deployed against them to be withdrawn.
The session was attended by 239 out of 450 MPs, most of them from opposition parties. But there were also dozens from the pro-Presidential Party of Regions.
Earlier the foreign ministers of France, Poland and Germany conducted several hours of discussions with Mr Yanukovych on a "roadmap towards a political solution" before going on to talks with opposition leaders.
They returned for another meeting with Mr Yanukovych on Thursday evening.
Polish Prime Minister Donald Tusk said Mr Yanukovych had expressed willingness to hold early elections this year.
The protests first erupted in November when President Yanukovych rejected a landmark association and trade deal with the EU in favour of closer ties with Russia.
Since then, the protests have spread across Ukraine, with the demonstrators' main demand being snap presidential and parliamentary elections.