Anti-government protesters were locked in a stand-off with riot police across burning barricades Wednesday after fierce clashes left at least 26 people dead in Ukraine's worst crisis since the collapse of the Soviet Union.
Anti-government protesters uses a slingshot during clashes with the police on Independence Square in Kiev early on February 19, 2014
The crackdown by security forces on Tuesday triggered a storm of international condemnation, with the White House calling the violence "completely outrageous".
In what could spell a policy U-turn on the three-month old crisis, the European Union called for an emergency meeting to discuss sanctions against those behind the unrest.
The French, German and Polish foreign ministers are also heading to Ukraine to meet embattled President Viktor Yanukovych Thursday in parallel with the EU crisis talks.
Ukraine's security service ramped up tensions by announcing a nationwide "anti-terrorist" operation, as the president accused the opposition of going too far.
Security forces on Kiev's Independence Square appeared to have temporarily halted their push to take over the main protest camp as people streamed to the site with food, clothing and medication for the demonstrators.
Some protesters on the smoke-filled square hurled Molotov cocktails and cobblestones at the lines of riot police, while others piled wood on to the burning barricades separating them from the security forces.
Riot officers responded with the odd volley of stun grenades and rubber bullets.
The atmosphere was more subdued than on Tuesday, when riot police stormed the square with tear gas and protesters responded by burning tyres and throwing stones and fireworks, leading to apocalyptic scenes of violence.
At the Winter Olympic Games in Sochi, shocked Ukrainian athletes wanted to wear black armbands to mourn the dead, but the request was denied by the International Olympic Committee as it would interfere with rules on athletes' clothing.
Tuesday's unrest was the deadliest since protests erupted in November after Yanukovych rejected an EU pact in favour of closer ties with former master Moscow.
Since then, the crisis has snowballed into a titanic tug of war for the country's future between Russia and the West.
- EU to explore 'all options' -
EU foreign policy chief Catherine Ashton summoned the bloc's foreign ministers for emergency talks on Thursday, with sanctions on the table.
"All possible options will be explored, including restrictive measures against those responsible for repression and human rights violations," she said.
France and Poland led the calls for sanctions, and were joined by the US, Britain and Germany in condemning the bloodshed.
"We stand with the men and women suffering" in Kiev, German Chancellor Angela Merkel said at a press conference with French President Francois Hollande in Paris.
US Secretary of State John Kerry said the international community was "deeply disturbed by the scenes of violence and the level of abuse".
And UN human rights chief Navi Pillay demanded an independent investigation into the unrest.
But in a televised address to the nation as the clashes raged, a defiant Yanukovych put the blame squarely on the opposition.
"The leaders of the opposition... have crossed the limits by calling for people to take up arms," he said.
Russia, which offered debt-laden Ukraine a $15 billion bailout after Yanukovych spurned the EU pact, described the protests as "an attempted coup d'etat".
Foreign Minister Sergei Lavrov called on the EU to press the opposition to cooperate with the authorities, even after accusing Western powers of meddling in Ukraine.
Ukraine's security service announced it would launch an anti-terror operation across the country against "radical and extremist groups".
It said about 1,500 firearms and 100,000 bullets had ended up in the hands of "criminals" over the past few days.
Kiev was effectively in lockdown on Wednesday as authorities shut down the metro and limited traffic into the capital. Schools in the centre were closed.
Ukraine's health ministry said 26 people had died in the clashes since Tuesday morning, including 10 policemen. Over 260 protesters and more than 340 police officers were injured.
A journalist working for a pro-government Kiev newspaper died of gunshot wounds after he was shot by masked men, his newspaper Vesti said.
The interior ministry added that 58 people had been detained.
Yanukovych called for a day of mourning on Thursday.
- 'Island of freedom' -
Tuesday's outbreak of violence surprised many, as tensions appeared to have been subsiding in recent days with both sides making concessions that saw protesters vacate Kiev city hall on Sunday after being granted an amnesty deal.
But on Tuesday, anti-Yanukovych protesters clashed with police outside parliament as they rallied for lawmakers to strip the president of a raft of powers.
Running battles broke out as protesters reoccupied city hall and attacked Yanukovych's party headquarters with petrol bombs.
Police descended on Independence Square in the evening, warning women and children to leave. But thousands of people, many wearing makeshift body protection and wielding iron bars and bats, stayed to battle the riot squads.
Late night talks Tuesday between Yanukovych and the opposition failed to go anywhere, prompting opposition leaders to urge protesters to stand their ground on the Maidan, as Independence Square is known.
"This is a small island of freedom," opposition leader and former boxing champion Vitali Klitschko said.
The violence also spread to the west of the country, where thousands of protesters overran public buildings.