Petr Pavlensky, the artist who this week nailed his scrotum to Red Square cobbles in protest at Russia's descent into a "police state", faces a prison term or a fine.

A police spokersperson confirmed to the Guardian that the artist had been charged with hooliganism, which carries a potential five-year jail sentence. Pavlensky, who is currently in Saint Petersburg, told the Guardian that investigators had summoned him to Moscow for questioning.

The Interfax news agency quoted a police source who specified that the charges referred to "ideologically motivated" hooliganism. The same vaguely worded clause of the Russian criminal code was applied to members of Pussy Riot who are serving two-year prison sentences.

On Sunday, Pavlensky squatted on the pavement in Red Square, naked, and hammered a nail through his scrotum into a gap between the cobble stones. The artist claims his performance was a protest against the "police state" and public apathy to it.

The potential punishments range from a large fine or community service to five years in prison. Unlike in the case of Pussy Riot, prosecutors chose not to detain Pavlensky pending trial. Given the absence of a propaganda campaign in the government-friendly media, a show trial on the scale of the Pussy Riot case looks unlikely.

The artist said he was ready for all eventualities, including prison. "It will be another nail in the regime's coffin. The authorities are discrediting themselves."

The jailed Pussy Riot member Nadezhda Tolokonnikova turned up this week in a Siberian prison hospital having been held incommunicado for 26 days. On Thursday, Tolokonnikova phoned her husband, Petr Verzilov, and reassured him her health was fine and that she preferred the Siberian prison to the one in Mordovia, where she was previously held.

Tolokonnikova has been admitted to Krasnoyarsk tuberculosis hospital but said she did not have TB, Verzilov said. She is being treated for health problems related to the hunger strike she waged as a protest against inhumane treatment in Mordovia.

The authorities have met one of Tolokonnikova's demands by moving her to another prison. They kept her whereabouts a secret during her transfer by train from European Russia to Siberia.

Authorities have not explained why a journey that normally takes a few days was extended for almost a month. "By comparison, it took 15 days for Dostoevsky to make a similar distance in horse-driven carts, when he was exiled to Siberia in the 19th century," Verzilov pointed out in a tweet.