The European Union has agreed to impose targeted sanctions on Ukraine - as escalating violence has seen up to 70 people killed in Kiev today.
Ministers meeting in Brussels say a travel ban and asset freeze on Ukrainians with what they call "blood on their hands", will be imposed "very rapidly".
The White House said earlier it was outraged that Ukrainian forces had fired on demonstrators after a short truce was broken.
At least 70 people have reportedly been killed after police fired live rounds at anti-government protesters near Independence Square in the Ukrainian capital, Kiev.
The claim was made by doctors working with the activists. Hundreds more demonstrators have been injured.
While protesters have taken 67 police officers prisoner, according to the interior ministry.
Hotel lobbies have been turned into makeshift hospitals, where some of the injured are given emergency treatment.
Meanwhile residents of Kiev have been warned by police not to go outside, and the Mayor of Kiev has resigned from the ruling party in protest over the bloodshed.
Opposition leader Vitali Klitschko said "Armed criminals and toughs were unleashed to beat people to show that there is conflict among people. But these plans are doomed".
Some Ukrainian athletes have left the Sochi Winter Olympics, an IOC spokesman said.
Tanaiste and Foreign Affairs Minister Eamon Gilmore is among those attending an Extraordinary Foreign Affairs Council in Brussels.
The fresh violence comes after he announced a truce with the opposition after violent clashes with riot police killed at least 26 people.
Three EU Foreign Ministers have met with the Ukrainian President, Viktor Yanukovych, for talks.
Russia has warned Ukraine's President not to let opponents walk over him "like a doormat", in a strong signal that Moscow wants order on the streets before handing over extra cash to stave off bankruptcy.
Moscow has also said that threats of sanctions from the West are "inappropriate".
The British Foreign Secretary William Hague called the Ukraine government's actions are "utterly indefensible".
The Ukrainian ambassador to Britain was summoned to the UK Foreign Office. Britain's Minister for Europe, David Lidington, is said to be "very angry" about the use of live fire.
Reporter Maxim Eristavi is in Kiev. He says he fears civil war is imminent.
'Police shooting with live rounds'
Reporter David Bowden said a "new front line" had emerged around 100 metres from the main square, after protesters pushed their way up a nearby street towards the government district. It caused police to "scurry away" to the top of the street, before launching a counter attack".
He said earlier "Police are hitting back and are shooting – probably not at random – but they are shooting with live rounds at the protesters. The police seem to have been caught off guard and they're reacting very aggressively and basically just shooting people".
"I've seen at least a dozen people pulled out injured. I do think this is going to be a fairly bloody day."
He added that police have weapons "of every denomination".
Tanya Mazur, Director of Amnesty International Ukraine is in Kiev and says many injured protesters are too scared to go to hospital.
