The foreign ministries of the UK, France, Sweden, Germany and the Netherlands issued a statement on Saturday saying they had concluded an analysis into death of Russian opposition leader Alexei Navalny.

The samples from the late politician, who died in prison two years ago, "have conclusively confirmed the presence of epibatidine," a deadly toxin that comes from a South American poison dart frog.

"Only the Russian state had the combined means, motive and disregard for international law," to carry out the killing, their statement said, adding that they would report the Kremlin to the Organization for the Prohibition of Chemical weapons for treaty violations.

"Russia claimed that Navalny died of natural causes. But given the toxicity of epibatidine and reported symptoms, poisoning was highly likely the cause of his death. Navalny died while held in prison, meaning Russia had the means, motive and opportunity to administer this poison to him," said the German Foreign Ministry.

"Navalny's poisoning must have consequences," German Foreign Minister Johann Wadephul added. 

UK Foreign Secretary Yvette Cooper added: "Russia saw Navalny as a threat. By using this form of poison, the Russian state demonstrated the despicable tools it has at its disposal and the overwhelming fear it has of political opposition."

Who was Alexei Navalny?

A former corporate lawyer, Navalny took to politics to fight widespread corruption and electoral fraud that observers say has long kept Putin's United Russia party in power.

He was imprisoned twice on embezzlement charges, which he and his widow Yulia Navalnaya say were fabricated to silence him. He survived an attempted poisoning with the Novichok nerve agent in 2020, a poison known to be used by Russian agents in political assassinations.

Navalny was jailed in a penal colony in the Arctic when officials announced that he had died on February 16, 2024.

Navalnaya said her late husband's killing was now proven by "science-proven facts' and thanked the investigators in a post on social media.

"Vladimir Putin is a murderer. He must be held accountable for all his crimes," she added.

Edited by: Louis Oelofse