Witnesses said riot police used truncheons, stun grenades and tear gas early on Saturday morning to disperse a crowd of some 400 protesters demanding the resignation of President Viktor Yanukovych.
Police reportedly arrested dozens of people, whom they said they later released. Government opponents also said that a number of protesters were injured in the police action.
Later in the morning, some anti-government demonstrators returned to the square outside Kyiv's St. Michael's Golden-Domed Monastery, shouting "shame" and "resign."
On Friday night, about 500 meters away from the monastery, 10,000 protesters had gathered in the capital's Independence Square, calling for Yanukovych to resign after he shelved an association agreement with the EU.
Wearing and carrying blue and gold, the colors of both the EU and Ukraine, protesters chanted "Ukraine is Europe."
Yanukovych last week abandoned plans to sign the deal, indicating a shift to instead build closer relations with Russia and other former Soviet republics. A last-minute compromise of a free-trade deal failed earlier on Friday, as EU leaders gathered in Vilnius for a summit on eastern European integration.
"We are demanding Yanukovych's resignation," said an opposition statement read by activist and singer Ruslana Lyzhichko. "We declare that we are continuing to fight for a European Ukraine," said Lyzhichko, who won the Eurovision song contest in 2004.
The rally had another celebrity attendee, in the form of heavyweight boxing champion Vitaly Klitschko. "Failure to sign the agreement of association is state treason," Klitschko told the crowd. "Today they stole our dream, our dream of living in a normal country," Klitschko said.
Critics of the government said their aim was to launch impeachment proceedings against Yanukovych, who said he was under pressure from Russia not to sign the EU agreement.
Scuffles near to square
In another brief episode of violence, four people - including a cameraman and photographer from the Reuters news agency - were beaten by police attempting to clear a road near to the square, the focal point of the 2004-2005 Orange Revolution which thwarted Yanukovych's first bid for the presidency.
That compromise deal would have allowed Yanukovych to sign a trade deal with Europe in the near future. EU leaders said the trade pact would bolster the Ukrainian economy by some 6 percent and would save Ukrainian businesses 500 million euros ($680 million) per year in import duties.
Among the EU's conditions for the deal, described by Yanukovych as "humiliating," are an implicit demand that Ukraine address the fate of jailed former Prime Minister Yulia Tymoshenko. Brussels has voiced concern over "selective justice" within Ukraine following the Tymoshenko's imprisonment in 2011 after being convicted of abuse of power while in office.
Brussels and Moscow are both keen to have the country of 46 million people, with its large land mass and rich mineral deposits, within their spheres of influence.
While the EU has dangled the carrot of possible future accession to the bloc, Russia is keen to avoid such a scenario, preferring that Ukraine instead join a Moscow-led customs union involving Belarus and Kazakhstan.
President Vladimir Putin has said he plans to develop that trading bloc into a Eurasian Economic Union.
rc,jr/tj (AP, dpa, Reuters)