Ukraine's political opposition on Saturday said it would call a country-wide general strike to force the resignation of President Viktor Yanukovich's government after police used batons and stun grenades to break up pro-Europe protests.
Helmeted police bearing white shields stormed an encampment in Kiev's Independence Square where protesters were singing songs and warming themselves by campfires early in the morning, the opposition said.
Tension had been building since Friday, when Yanukovich declined to sign a landmark pact with EU leaders at a summit in Lithuania, going back on a pledge to work towards integrating his ex-Soviet republic into the European mainstream.
Live bands had played earlier and the presence of mainly young people, some of whom were in their teens, had brought almost a party spirit to the demonstration.
The protests evoked memories of the "Orange Revolution" of 2004-5, led by jailed former prime minister Yulia Tymoshenko, against sleaze and election fraud which doomed Yanukovich's first bid for the presidency. But those protests were much larger and took place peacefully without police action.
Saturday's violence in which police fired stun grenades and then struck protesters with batons was unprecedented in Kiev and set the scene for possibly more confrontation on Sunday when a pro-Europe rally has been called. About 100,000 people turned out at a similar gathering last Sunday.
TV footage showed police beating one young woman on the legs during the early morning confrontation and kicking young men on the ground.
EU officials, who had attended the EU Vilnius summit with Yanukovich only days before, said they condemned what they called "excessive use of force".
"The unjustified use of force goes against the principles to which all participants of the Vilnius Summit," said a joint statement from European Union foreign policy chief Catherine Ashton and EU enlargement chief Stefan Fuele.
Yanukovich has promised his long-term commitment to Europe and has said the suspension in signing the agreement on association is only a temporary measure because the cost of upgrading the economy to meet EU standards was too great.
The Interior Ministry said the riot police moved in "after the protesters began to resist the (ordinary uniformed) police, throwing trash, glasses, bottles of water and flares at them".
Police detained 35 people but later released them, it said. There were no clear figures on how many people were hurt.
Ukraine's opposition condemned the crackdown and threatened a nationwide strike while demanding the government's resignation and early parliamentary and presidential elections.
"We have taken a common decision to form a task force of national resistance and we have begun preparations for an all-Ukraine national strike," former economy minister Arseny Yatsenyuk, one of three opposition leaders, told journalists.
Nearly 10,000 protesters regrouped on Saturday, some of them holding candles, at Mikhailovska Square near a monastery where protesters had taken refuge from the police violence.
Among chants of "Rise up Ukraine", former interior minister Yuri Lutsenko, an ally of Tymoshenko who himself was released from a jail sentence earlier this year, encouraged a strike as early as Monday.
"From Monday, Kiev should be blocked and this strike will take away the power of the bandits," he said referring to corrupt politicians and powerful businessmen who Ukrainians say derive their wealth from their political ties with Yanukovich.
'NO LONGER UKRAINE'
The protesters were mainly young supporters from the main three opposition parties - including that of Tymoshenko - who are united in pressing for a westward shift in policy towards the European Union.
Tymoshenko, whom the EU sees as a political detainee, issued a call for people "to rise up" against Yanukovich.
"Millions of Ukrainians must rise up. The main thing is not to leave the squares until the authorities have been overthrown by peaceful means," she said in a letter read to journalists by her daughter.
Police cleared away anti-Yanukovich posters and political graffiti and took down flags and banners, including the EU blue and gold standard, before sealing off the area.
After the police action, the remnants of the protest, about 100 people, shifted to St. Michael's cathedral - a 12th century monastery destroyed by Soviet authorities in 1937 and rebuilt after independence in 1991.
"We gathered here after riot police beat us and chased us out of the square. It's the only safe place we could go to," said Roman Tsaldo, 25.
Heavyweight boxing champion turned opposition politician Vitaly Klitschko said: "After the savagery we have seen on Independence Square we must send Yanukovich packing."
At least four people were beaten by police earlier on Friday, including a Reuters cameraman and a Reuters photographer, who was bloodied by blows to the head by police.