Investigators in Moscow have launched a probe into opposition politician Aleksei Navalny’s interview with the Ekho Moskvy radio station.

According to sources quoted by the official TASS news agency on December 1, investigators allege that in the April 27 interview Navalny called for the forcible change of Russia’s constitutional order.

“Due to the statements [in the interview], a probe was launched on November 30 to check if there were elements of calls to conduct extremist activities,” a source was quoted by TASS as saying.

The Russian Criminal Code lays out a punishment of up to five year in prison for such a crime.

Talking to Ekho Moskvy on April 27, Navalny criticized the Kremlin for rejecting his team’s proposal to provide Russian families and small businesses with financial support during the ongoing coronavirus pandemic, and said that the authorities in Russia “must be overthrown right now…most likely by force” for neglecting the needs of citizens.

The program’s anchor then directly pointed to the statements as being merely Navalny’s thoughts, not open calls to overthrow the government, which Navalny confirmed in the aired interview.

Navalny is currently in Germany, where he is recovering after being poisoned with a Novichok nerve agent in Siberia in late August.

Navalny has insisted that Russian President Vladimir Putin ordered the poisoning attack on him. The Kremlin has denied any involvement.

On December 1, Navalny wrote on Instagram that the probe was launched on Putin’s order to prevent his return to Russia after a full recovery.

In October, the European Union and Britain imposed asset freezes and travel bans against six senior Russian officials and one entity for the “attempted assassination” of the outspoken, 44-year-old Kremlin critic.

Last week, Navalny called on the EU to develop a new strategy for its relations with Moscow and impose more sanctions on the Kremlin.