Ukrainian police and protesters on Wednesday engaged in ferocious clashes in the centre of Kiev, leaving five activists dead in the first fatalities in two months of anti-government protests.
An area in the centre of the capital was turned into a virtual war zone as protesters hurled stones and Molotov cocktails at police and the security forces responded with tear gas, stun grenades and rubber bullets.
The opposition movement's medical service said that five of its activists had been killed and four of them reported found with gunshot wounds. Prosecutors have so far confirmed two deaths.
The bloody clashes marked a new peak in tensions after two months of protests over the government's failure to sign a deal for closer integration with the European Union under Russian pressure.
Ukrainian opposition leaders said the next 24 hours would be crucial as they waited to hear from President Viktor Yanukovych if he would accept concessions to halt the bloodshed.
The epicentre of the clashes was Grushevsky Street in the city centre which has been the scene of three days of street battles between thousands of protesters and similar numbers of security forces.
Police launched a major assault on protesters there in the morning, initially pushing demonstrators back well beyond their initial lines by marching forward in military formation.
But the protesters then regrouped, creating a semi-circle of new barricades out of burning black tires whose rancid smoke filled the skies above Kiev and flames burned in near-apocalyptic scenes.
Police for the first time started moving an armoured personnel carrier towards the protesters after storming the barricades.
Meanwhile tens of thousands thousands Wednesday evening filled Independence Square in Kiev which was the main protest hub for the last two months, hoping their sheer numbers would deter further action.
They sought to reinforce the protest barricades by several metres by filling sandbags with snow and brought new tires for burning on the frontline.
Opposition figure warns president to yield
Yanukovych on Wednesday met with opposition leaders, including former world boxing champion Vitali Klitschko in a meeting that went on for several hours.
Klitschko told the crowds on Independence Square after the talks that Ukrainian protesters will go "on the attack" if Yanukovych does not swiftly offer concessions.
"If Yanukovych does not make concessions, then tomorrow (Thursday) we will go on the attack," Klitschko said, adding the president could resolve the situation without bloodshed by giving way to the chief demand of early elections.
He said the talks with Yanukovych would continue but gave no indication they were close to any breakthrough.
A former MP from Yanukovych's Region's Party who switched sides during the protest, Inna Bogoslovska, bluntly told the rally the authorities were doomed: ?Viktor Fyodorovich, this is the end," she said.
US imposes visa ban, EU warns of action
The deadly violence horrified Ukrainians, who have never witnessed such scenes in their country including during the 2004 Orange Revolution which was almost entirely peaceful.
Amid growing international concern, EU foreign policy chief Catherine Ashton on Wednesday urged "an immediate end" to the escalating violence.
European Commission president Jose Manuel Barroso on Wednesday warned the authorities that the EU executive authority would assess "possible actions" against the Ukrainian authorities.
The United States also revoked the visas of several Ukrainian nationals linked to violence against protesters in November and December last year, the US embassy said in a statement.
But Russia, which has regarded Ukraine's pro-EU protest movement with suspicion from the start, took a different view and blamed the opposition and West for the clashes.
"Ukraine's legitimate authorities face outside interference in its internal affairs," Russian Deputy Foreign Minister Grigory Karasin told the Interfax news agency, referring to EU and US statements.
First deaths in protests
Oleg Musiy, the coordinator of the medical service, told pro-opposition Hromadske radio, that five people have been killed and around 300 wounded.
According to the Ukrainska Pravda news website, four of the five people found dead had gunshot wounds.
One of the activists was killed after falling from the top of the ceremonial entrance to Dynamo Kiev stadium adjacent to the protests, according to Ukrainian media.
The clashes made a mockery of Ukraine's annual day of unity which celebrates the unification of western and eastern Ukraine in 1919.
The government is basing its actions on a new set of laws, which ban nearly all forms of protest in the ex-Soviet country and have enraged demonstrators.
They allow for jail terms of up to five years for those who blockade public buildings and the arrest of protesters wearing masks or helmets.
Meanwhile a prominent Ukrainian activist and journalist, Igor Lutsenko, on Wednesday appeared in public after being abducted from a hospital by unknown individuals and dumped in a forest outside Kiev.
He had been taken from a hospital in Kiev, beaten, and was eventually left in a forest by his abductors after an ordeal lasting almost a day.
However a man abducted with him, an activist named Yuriy Verbitsky has not been found, and a relative told Ukrainian media that he had been killed in a forest and she had identified his body in a local morgue.