An investigation by Bellingcat, an Internet research organization, and other media outlets, revealed that for years, Russian agents secretly followed Alexei Navalny.

In an interview, the Russian opposition leader accuses President Vladimir Putin of ordering the attack with the Soviet-era nerve agent Novichok. A Kremlin spokesperson calls the accusation groundless.

A spokeswoman says the Russian opposition leader's bank accounts were frozen and his Moscow apartment "seized" in connection with a libel suit while he was in a coma after poisoning by a nerve agent.

Navalny spent 32 days in Berlin's Charité Hospital, 24 of them in intensive care. Independent lab tests in three countries confirmed he had been poisoned by a Soviet-era nerve agent.