Ukrainian President Viktor Yanukovich has said he was "deeply outraged" by incidents at a pro-Europe rally in the capital Kiev which had led to violent confrontation between protesters and police, and caused injury.
Early on Saturday, riot police broke up a rally by protesters in Kiev using batons and stun grenades and an undisclosed number of people were injured.
In an address to Ukrainians carried on his web site, he called for an immediate and objective investigation so that
those guilty could be punished, though he did not specifically blame the police for the incidents.
About 10,000 anti-government demonstrators angry about Ukraine's refusal to sign a pro-European Union agreement converged on a square outside a monastery where protesters driven away in a pre-dawn clash with police were taking shelter.
Opposition leaders called for nationwide strikes and for Ukrainians to mobilise en masse. Another big demonstration was called for Sunday.
The demonstrators outside the St Michael's Golden-Domed Monastery were shouting "shame" and "resign." Some vowed to spend the night on the square, as temperatures hovered only slightly above freezing.
"Each of you have to come out and express your own position on what kind of country you want to live in - a totalitarian, police-controlled country where your children will be beaten up or in a European country," said Vitaly Klitschko, a world boxing champion and leader of the opposition Udar party.
Klitschko's call encapsulated the two issues agitating the demonstrators: President Viktor Yanukovych's refusal to sign an association agreement with the EU and the violent dispersal of protests denouncing that decision.
Yanukovych said in an address Saturday evening that he condemned "the actions that led to the forceful confrontation and the suffering of people."
He called for an investigation and for those responsible to be punished.
"I confirm that we are united in our choice of a common European future," Yanukovych said.
Yanukovych has said he still hopes that Ukraine will one day sign the agreement with the EU, but that the country was too fragile economically and could not afford to sacrifice trade with Russia.
Moscow regards Ukraine as historically part of its orbit and has tried to block the deal with the EU by banning some of Ukraine's imports and threatening more trade sanctions. A 2009 dispute between Kiev and Moscow on gas prices resulted in a three-week cutoff of gas to Ukraine.
The association agreement would have established free trade and deepened political cooperation between Ukraine and the EU, but stopped short of membership in the regional bloc.
Source: Al Jazeera and agencies