Protesters have clashed with riot police outside a court building in Kiev, the capital of Ukraine.
Three men were sentenced to six years in prison for plotting to blow up a statue of Soviet founder Lenin near the city's main airport in 2011.
The BBC reports several people were injured in the clashes early on Saturday. Former interior minister Yuriy Lutsenko, 49, was among them.
State television in Russia said anti-riot troops moved in after being pelted with rocks by protesters who were trying to block police vans as the three convicts were being led out of court in order to be taken in prison.
Anti-government protests began in November after President Viktor Yanukovych abandoned a trade agreement with Europe in favour of closer cooperation with Russia.
Russia has since cut the price of gas to Ukraine and invested $US15 billion in government bonds.
The rallies intensified after beat dozens of demonstrators were beaten by police in Independence Square in Kiev on 30 November.