A Russian court Tuesday ordered that an activist be committed to a mental hospital after convicting him for his role in a protest against President Vladimir Putin, a move criticised as reviving Soviet-era punishments. In its verdict, the Moscow court found activist Mikhail Kosenko, who suffers from a mild form of schizophrenia, guilty of participating in an anti-Putin mass protest and using violence against police. The judge however ruled that due to his illness, Kosenko, 38, was mentally incompetent and must be admitted to a high-security psychiatric facility indefinitely. "The court ruled that Kosenko undergo compulsory medical treatment," his lawyer Valery Shukhardin told AFP. Diagnosed with "sluggish schizophrenia" -- a term for mild mental illness used in Russia -- Kosenko had been treated on an outpatient basis before his pre-trial detention. His defence insists that he should not be hospitalised and continue treatment as an outpatient. But a psychiatric report submitted to the court by the prosecution said his schizophrenia was so serious he needed to be committed. "A conclusion by expert psychiatrists says that he is a danger to society and therefore should be isolated in a psychiatric facility," said Shukhardin. "It's unclear to us where these conclusions come from. They are not justified by anything except the charges laid against him." Kosenko was one of a dozen activists accused of mass disorder when a peaceful opposition protest suddenly descended into violence on May 6 last year, on the eve of Putin's inauguration to a third presidential term. A group of Kosenko's supporters gathered outside the Moscow court, some holding white flowers that symbolise the anti-Putin opposition movement, shouting "Shame!" Nine people were detained, police said. Kosenko had denied the charges, insisting he did not attack a policeman as alleged but simply pushed him away. Shukhardin said the court ruling could see Kosenko spend several years in a psychiatric ward. 'Smacks of worst Soviet excesses' Veteran human rights activist Lyudmila Alexeyeva, who has monitored the trial, called the ruling "a resumption of the psychiatric persecutions for dissent that were practised in the Soviet Union." "Now they have started it again.... Butchers," she told AFP. The Soviet Union regularly diagnosed political dissidents with mental illnesses and incarcerated them in psychiatric hospitals for years on end. John Dalhuisen, Europe and Central Asia programme director at Amnesty International, said in a statement that the ruling "smacks of the worst excesses of the now defunct Soviet era." The watchdog last week called Kosenko and two other activists "prisoners of conscience," saying the video footage presented in court did not corroborate the prosecution's charges. The Moscow-based Independent Psychiatric Association said earlier this month that Kosenko's case would set a dangerous precedent. "The political use of psychiatry has been resurrected," it said. Kosenko has been held in pre-trial detention since June last year. When his mother died recently he was not allowed to attend her funeral. Kosenko's lawyer said his health had deteriorated over the past month because he had not been issued the correct medication. Russian opposition leader Alexei Navalny, who has also closely monitored the trial, called Kosenko "an example for us all." The opposition has maintained that the scuffles with police at the May 2012 rally in Moscow came as a result of a police provocation. Authorities, however, have said protesters deliberately attacked police. Rights activists say the trial is part of a tough crackdown on the opposition after unprecedented protests against Putin's 13-year rule. In November 2012, another participant in the protest, Maxim Luzyanin, was sentenced to four-and-a-half years in prison after pleading guilty. A third participant, Konstantin Lebedev, was jailed for two-and-a-half years in April.