Russian Opposition Leader Alexei Navalny Likely Died From Blood Clot: Ukrainian Spy Chief

‘I may disappoint you, but as far as we know, he indeed died as a result of a blood clot,’ the spy chief said.

A man holds a portrait of Kremlin critic Alexei Navalny during a vigil at Rome's city hall, on Feb. 19, 2024. Filippo Monteforte/AFP via Getty Images

Ukraine’s intelligence chief said on Sunday that Russian opposition leader Alexei Navalny most likely died of a blood clot, amid speculation that he was assassinated while in prison.

Mr. Navalny, 47, has been the most prominent critic of Russian President Vladimir Putin’s government over the past decade. He collapsed and died in a Siberian prison camp on Feb. 16, according to Russian officials.

Kyrylo Budanov, chief of the Main Directorate of Intelligence of Ukraine’s Ministry of Defense, told reporters on Feb. 25 that Mr. Navalny possibly died from natural causes.

“I may disappoint you, but as far as we know, he indeed died as a result of a blood clot. And this has been more or less confirmed,” Mr. Budanov was quoted as saying by Kyiv Post.

“This wasn’t sourced from the internet, but, unfortunately, natural [causes],” he added.

His remarks came just a day after the Group of Seven nations issued a statement calling on the Russian government to “fully clarify” the circumstances around Mr. Navalny’s death.

“He sacrificed his life fighting against the Kremlin’s corruption and for free and fair elections in Russia,” the statement reads.

“We will hold those culpable for Navalny’s death accountable, including by continuing to impose restrictive measures in response to human rights violations and abuses in Russia and taking other actions.”

The leaders also urged the Russian government to release “all unjustly detained prisoners” and “to stop the persecution of political opposition and the systematic repression of Russians’ rights and freedoms.”

Mr. Navalny had been incarcerated since January 2021, following his return to Moscow from Germany. He received three prison sentences totaling more than 30 years.

Russian authorities reported that Mr. Navalny felt unwell after a walk at the IK-3 penal colony in Kharp, one of 700 labor camps currently operating in Russia. It’s located about 1,900 kilometers (1,181 miles) northeast of Moscow in the Arctic Circle. He lost consciousness almost immediately, authorities reported.

Western leaders paid tribute to Mr. Navalny’s courage as a fighter for freedom. Some, without citing evidence, accused the Kremlin of murder and said the Russian leader should be held accountable.

“Russian authorities are going to tell their own story. Make no mistake. Putin is responsible for Alexei Navalny’s death,” President Joe Biden told reporters on Feb. 16.

“There is no doubt that the death of Navalny was a consequence of something that Putin and his thugs did,” he added.

Russian opposition leader Alexei Navalny and other demonstrators march in memory of murdered Kremlin critic Boris Nemtsov in downtown Moscow, on February 29, 2020. Kirill Kudryavtsev/AFP via Getty Images

Russian officials portrayed Mr. Navalny as an extremist and a puppet of the CIA. When protests against Mr. Putin erupted in December 2011, he was among the first protest leaders arrested.

There are no other opposition leaders in Russia of his stature. For some young urban Russians, Mr. Navalny offered hope of a future different from the one envisioned under President Putin, who has served as Russia’s paramount leader longer than anyone since Josef Stalin.

Emel Akan and Reuters contributed to this report.