Ukraine's ex-interior minister and current opposition leader Yuriy Lutsenko was under intensive care in hospital Saturday after being beaten in fresh clashes that erupted between pro-EU demonstrators and club-wielding police.
A few hundred nationalist demonstrators protested late Friday outside a Kiev court that had earlier in the day sentenced three men to six years in prison for allegedly plotting to blow up a statue of Soviet founder Lenin near the city's main airport in 2011.
Ukrainian television showed several protesters being carried by stretcher to an ambulance that had been rushed to the scene. A parliamentary human rights ombudsman said 11 opposition members had been injured and that one person besides Lutsenko remained hospitalised overnight.
Russian state television said the Berkut anti-riot troops began firing tear gas and making arrests after being pelted with rocks by protesters who were trying to block police vans as the three convicts were being led out of the courthouse.
Ukraine's interior ministry added that 20 of its officers had been injured.
Opposition news sites published photographs and video images of Lutsenko with his head bandaged and a large patch over his right eye.
Lutsenko's wife Irina said her husband had suffered a concussion and head injuries after being attacked by police while he was trying to break up the unfolding violence.
"He has been placed in intensive care. They are going to keep him under observation," she told Ukraine's opposition Hromadske television channel.
Lutsenko's spokeswoman Larisa Sargan said the opposition leader lost consciousness several times on his way to hospital.
"He received about 10 blows to the head," she told the online edition of Kiev's Segodnya daily.
Ukrainian nationalists have been a driving force behind anti-government protests that erupted in November after President Viktor Yanukovych ditched a historic EU trade agreement in favour of closer ties with old master Russia.
The rallies were fanned further by anger over violence that broke out when hundreds of officers beat dozens of demonstrators while trying to clear them off Kiev's iconic Independence Square on November 30.
The latest outbreak of violence in Kiev drew no immediate response from Yanukovych or his government members.
But the Kiev prosecutor's office said it had launched an investigation into both the actions of protesters and the police.
"Kiev prosecutors have opened criminal proceedings into abuse of power (by the police)," the prosecutor's office said in a statement.
It added that protesters were being investigated for "hooliganism, the illegal interference in the work of a court, and resisting police."
The first Kiev clashes of the new year threaten to re-energise rallies that began to fizzle out last month when Yanukovych signed a $15-billion economic bailout agreement with Moscow that also slashed the price Ukraine pays for Russian gas imports.
Anti-government forces are planning another mass Independence Square rally for Sunday afternoon.
Lutsenko was a prominent member of former prime minister Yulia Tymoshenko's pro-Western government and remains a close ally of the jailed opposition leader.
The 49-year-old was himself put in prison on contested charges in late 2010 and pardoned by Yanukovych under EU pressure in April 2013.