Navalny was arrested in 2021 upon his return to Russia from Germany where he had been treated for a suspected assassination attempt by poison.

　　It is unclear where the body of Russian opposition leader Alexei Navalny is, his team said on Saturday after confirming his death, demanding his remains be released to his family "immediately".

　　They added that the Kremlin critic had been "murdered".

　　Navalny's spokesperson,?Kira Yarmysh, posted on X that Navalny's mother had travelled to the "special regime" penal colony above the Arctic Circle he had been held in and been given an official message that he had died on February 16 at 2:17 p.m. local time.

　　She was then informed that his body had been transferred by investigators to?Salekhard.

　　But when she, and his lawyer, arrived at the morgue, it was closed. "The lawyer called the phone number which was on the door. He was told he was the seventh caller today. Alexei's body is not in the morgue," Yarmysh wrote.

　　“We demand that Alexey Navalny’s body be handed over to his family immediately,” she also wrote.

　　Russia’s Federal Penitentiary Service reported that Navalny felt sick after a walk and became unconscious at the penal colony in the town of Kharp, in the Yamalo-Nenets region about 1,900 kilometres northeast of Moscow. An ambulance arrived, but he couldn’t be revived. The cause of death is still “being established,” it said.

　　Maria Pevchikh, head of the board of Navalny’s Anti-Corruption Foundation, said that the opposition leader would “live on forever in millions of hearts.”

　　“Navalny was murdered. We still don’t know how we’ll keep on living, but together, we’ll think of something,” she wrote on X.

　　Arrests continued Saturday after more than 100 people were detained in various Russian cities Friday when they came to lay flowers in memory of Navalny at memorials to the victims of Soviet-era purges, according to OVD-Info, a group that monitors political repression in Russia.

　　The tributes were removed overnight, but people continued trickling in with flowers on Saturday. In Moscow, a large group of people chanted “shame” as police dragged a screaming woman from the crowd, video shared on social media showed.

　　More than 10 people were detained at a memorial in St. Petersburg, including a priest who came to conduct a service for Navalny there.

　　In other cities across the country, police cordoned off some of the memorials and officers were taking pictures of those who came and writing down their personal data in a clear intimidation attempt.

　　Navalny had been jailed since January 2021, when he returned to Moscow to face certain arrest after recuperating in Germany from nerve agent poisoning he blamed on the Kremlin. He was later convicted three times, saying each case was politically motivated, and received a sentence of 19 years for extremism.

　　After the last verdict, Navalny said he understood he was “serving a life sentence, which is measured by the length of my life or the length of life of this regime.”

　　The news of Navalny’s death comes less than a month before an election that will give President Vladimir Putin another six years in power.

　　It shows “that the sentence in Russia now for opposition is not merely imprisonment, but death,” said Nigel Gould-Davies, a former British ambassador to Belarus and senior fellow for Russia & Eurasia at the International Institute for Strategic Studies in London.

　　Western leaders have largely held the Kremlin and President Putin responsible for Navalny's death with?European Council President Charles Michel writing on X that "the EU holds the Russian regime (solely) responsible for this tragic death."