The sentence came into force after the Court of Appeal ruling.
Radkevich, who earlier served in the Soviet army, told the court earlier he could not attend the hearing in Vilnius in person as he was now fighting to defend Ukraine against Russian aggression.
Earlier he notified the court in writing that he acknowledged his guilt and asked the Court of Appeal to release him from criminal responsibility or at least reduce his sentence.
Several years ago, Vilnius Regional Court sentenced Radkevich, now 53, to four years in prison for driving a tank involved in the bloody January 13, 1991 events at the Lithuanian capital's Press House.
Last fall, Radkevich was detained in Greece on a European arrest warrant issued by a Lithuanian court. However, the Supreme Court of Greece ruled on February 9 not to extradite the man to Lithuania and he was released.
Radkevich is one of 67 people handed prison sentences in the mass trial. The majority of the defendants were convicted in absentia as Russia and Belarus refused to extradite them.
Fourteen civilians were killed and hundreds more were injured when the Soviet troops stormed the TV Tower and the Radio and Television Committee building in Vilnius in the early hours of January 13, 1991.
The Soviet Union used military force in its attempt to remove the legitimate government of Lithuania which declared independence on March 11, 1990.