Charges against the critic of Russia’s President Vladimir Putin could extend his prison sentence by decades.

Monday’s court hearing took place at the IK-6 penal colony in Melekhovo, where Navalny is being imprisoned, about 235km (145 miles) east of Moscow.

He looked thin, had cropped hair and was dressed in a black prison uniform, according to journalists in Russia, who were allowed to cover the court proceedings virtually.

In an effort to contest the court’s charges, Navalny said: “Taking into account the current circumstances, and criminal law, you should withdraw.”

The critic of Russia’s President Vladimir Putin is already serving an 11.5-year prison sentence over fraud and other charges, accusations he says are trumped up.

He says the new charges of “terrorism” issued against him in April are an “absurd” attempt to further silence him.

Navalny’s team members fear the new charges could keep him in prison for up to 30 years and claim he has not been notified of the specifics, because he was in solitary confinement where he was allowed only a mug and one book.

Court papers last month showed the new charges relate to six different articles of the criminal code, including inciting and financing extremist activity and creating an extremist organisation.

Kremlin spokesman Dmitry Peskov said the Russian government was “not following this trial”.

Last week Navalny’s aide Lilia Chanysheva was also sentenced to seven and a half years in prison for “creating an extremist organisation”, a court ruling Navalny’s supporters have said was “politically motivated”.

But it is not yet clear which events these extremism charges relate to.

According to Reuters, one relates to “rehabilitation of Nazism” – a possible reference to Navalny’s declarations of support for Ukraine.

Ukraine and its Western allies dismiss that charge as baseless.

In April, Russian investigators linked Navalny to the death of the popular military blogger Vladlen Tatarsky, who was killed by a bomb in a St Petersburg cafe. Navalny’s allies have denied any connection.

Navalny, a former lawyer, rose to prominence more than 10 years ago by alleging large-scale corruption in his country.

He returned to Russia in 2021 from Germany, where he was treated for what tests showed was an attempt to poison him with a nerve agent in Siberia.

The Kremlin has repeatedly denied trying to kill him and often declines to comment on the imprisonment of Navalny and his supporters.