Russia on Friday ruled radical performance artist Pyotr Pavlensky must stay in pre-trial detention until January after he set fire to the door of the feared security service's headquarters.
Judge Marina Orlova at Moscow's Tagansky district court extended his detention in prison to January 7, saying he could otherwise flee, RIA Novosti news agency reported.
Late on November 8, Pavlensky posed for a photograph holding a petrol canister in front of the blazing door of the FSB security service headquarters in central Moscow, previously the home of the KGB.
He said the performance was to protest against "terrorism" by the state security services.
The 31-year-old artist nailed his scrotum to the ground on Red Square in a previous protest against excessive police powers.
Russia has taken a harsh stance towards Pavlensky's performance in a case that has already prompted comparisons with Pussy Riot punk rockers, sentenced to two years in 2012 for a protest against President Vladimir Putin in a church.
Pavlensky has been charged with vandalism, for which he could serve up to three years in prison.
Since the performance, he has been held in custody in a Moscow prison because the prosecution says he could flee the country or re-offend.
Investigators on Friday insisted he must also undergo testing of his mental capacity in a psychiatric hospital.
Pavlensky has already been tested three times after previous extreme performances and found mentally competent.
He has refused to answer questions on the case from the judge unless she reclassifies his case as "terrorism" or drops the charges altogether.
A Moscow higher court on Thursday had rejected an appeal against his detention behind bars.
Pavlensky already risks jail for vandalism over a separate performance in which he and others set tyres on fire in Saint Petersburg to simulate Ukraine's pro-European Maidan Square uprising last year.
