European leaders said they are confident Navalny was poisoned with a toxin found in South American poison dart frogs.

Two days before the second anniversary of Alexey Navalny’s death, five European countries declared that independent forensic analyses show the opposition leader was poisoned in prison. The substance reportedly used to kill Navalny was the neurotoxin epibatidine — an allegation Russian authorities dismissed as “a planted fabrication.

Russian opposition leader Alexei Navalny died in prison after being poisoned with a deadly toxin found in Ecuadorian dart frogs, the U.K. and other allies claimed Saturday

The Kremlin has rejected the claim from several European nations and the widow of Russian opposition leader Alexei Navalny that Moscow silenced the critic using a poisonous substance found in South American dart frogs.

In a joint statement, the foreign ministries of the U.K., France, Germany, Sweden and the Netherlands say Navalny was poisoned by Russia with a lethal toxin derived from the skin of poison dart frogs.

There is no innocent explanation for the toxin, called epibatidine, being found in samples taken from Navalny's body, the Foreign Office said.

"Only the Russian state had the means, motive and opportunity," the U.K. said.

Navalny died, aged 47, in an Arctic prison colony in February 2024, after being convicted of extremism and other charges, all of which he denied. Russian authorities said the politician became ill after a walk and died from natural causes.

Five European countries say tests confirm Russian opposition leader Alexei Navalny was poisoned with a lethal toxin found in poison frogs, and they blame the Russian state.

Mourners gathered in Moscow on Monday to mark two years since the death in custody of Russian opposition leader Alexei Navalny, under the shadow of a Kremlin crackdown and just two days since a new analysis reinforced suspicions that he was murdered.