Aleksei Navalny, Russian Opposition Leader, Dies in Prison at 47

Aleksei A. Navalny, an anticorruption activist who for more than a decade led the political opposition in President Vladimir V. Putin’s Russia while enduring arrests, assaults and a near-fatal poisoning, died Friday in a Russian prison, according to Russia’s Federal Penitentiary Service. He was 47.

The prison authorities said that Mr. Navalny lost consciousness on Friday after taking a walk in the Arctic penal colony where he was moved late last year. He was last seen on Thursday, when he had appeared in a court hearing via video link, smiling behind the bars of a cell and making jokes.

Kira Yarmysh, Navalny’s press secretary, said in a live broadcast Friday that Navalny’s advisers were not yet able to issue an official confirmation of his death but believed that he had perished. And while acknowledging that the United States did not know the details of what happened, President Biden at a White House news conference said, “Make no mistake: Putin is responsible for Navalny’s death.”

Mr. Navalny had been serving multiple sentences that would most likely have kept him in prison until at least 2031 on charges that his supporters say were largely fabricated in an effort to muzzle him. Despite increasingly harsh conditions, including repeated stints in solitary confinement, he maintained a presence on social media, while members of his team continued to publish investigations into Russia’s corrupt elite from exile.

Mr. Navalny was given a three-and-a-half-year prison sentence in February 2021 after returning to Russia from Germany, where he had been recovering from being poisoned the previous August. In March 2022, he received a nine-year sentence for embezzlement and fraud in a trial that international observers denounced as “politically motivated” and a “sham.” And in August 2023, he was sentenced to 19 years in prison for “extremism.”