A person lays flowers at the grave of Russian opposition leader Alexei Navalny while marking the first anniversary of his death at a cemetery in Moscow, Russia, February 16, 2025. REUTERS/Evgenia Novozhenina MOSCOW,

Russian opposition leader Alexei Navalny was poisoned by the Kremlin with a rare and lethal toxin found in the skin of poison dart frogs, five European countries said Saturday.

Traces of epibatidine were found in samples from Navalny's body and highly likely resulted in his death in a Siberian penal colony two years ago, the UK Foreign Office said.