Russian police have detained more than 400 people at spontaneous memorials for opposition figure Alexei Navalny, who died in prison on Friday while <a href="https://www.thenationalnews.com/world/2023/08/04/navalny-jailed-for-further-19-years-on-extremism-charges/" target="_blank">serving a 19-year term</a>. Authorities said the 47-year-old Kremlin critic <a href="https://www.thenationalnews.com/world/europe/2024/02/16/alexei-navalny-putin-russian/" target="_blank">fell ill after a walk</a> and died at the Arctic prison colony where he was being held. The announcement prompted grief among his supporters and condemnation internationally by world leaders who said Russia was to blame. Mr Navalny's death was confirmed by his spokeswoman, Kira Yarmysh, on Saturday, quoting an official notice given to his mother, Lydumila. Writing on social media, she quoted the notice as saying that Mr Navalny had died at 2.17pm local time and that his body was in Salekhard, a town near the Arctic prison where he was held. She demanded that the body be immediately released to his family. Ivan Zhdanov, the director of Mr Navalny’s Anti-Corruption Foundation, wrote on X that Mr Navalny’s mother had been told by prison officials that her son succumbed to “sudden death syndrome”, after she arrived at his former penal colony on Saturday with one of the politician’s lawyers. The lawyer called the mortuary and was told that Mr Navalny's body was not there, his team said. Another of Mr Navalny’s lawyers went to Salekhard’s Investigative Committee and was told that the cause of his death had not yet been established and that investigations are being done with the results to be released next week, Ms Yarmysh said. Mr Navalny's supporters gathered to place flowers at makeshift monuments across<a href="https://www.thenationalnews.com/tags/russia/" target="_blank"> Russia</a> late on Friday, and in some cases were detained by police, footages on social media showed. In <a href="https://www.thenationalnews.com/world/us-news/2024/02/07/tucker-carlson-interview-vladimir-putin/" target="_blank">Moscow</a>, on Friday night, as police looked on, a group of people removed flowers from a memorial near the headquarters of Russia's Federal Security Service. OVD-Info, which reports on freedom of assembly in Russia, said the largest numbers of arrests on Saturday occurred in St Petersburg and Moscow, where Mr Navalny's movement had traditionally been strong, with 74 and 49 detained. But by morning, more flowers had appeared. Protests are illegal in Russia under anti-dissent laws, and authorities have clamped down particularly harshly on rallies in support of Mr Navalny. Authorities in the Russian capital said on Friday that they were aware of calls online “to take part in a mass rally in the centre of Moscow” and told people not to attend. As of Saturday evening, 401 people had already been detained in 36 cities, said OVD-Info. Police blocked access to a memorial in the Siberian city of Novosibirsk on Saturday and detained several people there, as well as in another Siberian city, Surgut, OVD-Info said. Videos shared on social media from Novosibirsk showed people sticking red flowers upright in the snow under the eye of police, who used tape to block access to the memorial. The news of Mr Navalny's death came less than a month before an election that will give <a href="https://www.thenationalnews.com/business/economy/2024/02/09/russia-sanctions-tucker-carlson-putin-interview/" target="_blank">Russian President Vladimir Putin</a> 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 and Eurasia at the International Institute for Strategic Studies think tank in London. The circumstances of Mr Navalny's death are still largely unclear. Russia’s Federal Penitentiary Service reported that Mr Navalny felt sick after a walk and lost consciousness at the penal colony in the town of Kharp, in the Yamalo-Nenets region about 1,900km north-east of Moscow. An ambulance arrived, but he could not be revived, and the cause of death was still “being established”, it said. Mr 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, Mr Navalny said he understood he was “serving a life sentence, which is measured by the length of my life or the lifespan of this regime”. In a documentary filmed before he returned to Russia, Mr Navalny was asked what message he wanted to leave to the Russian people should he die or be killed. “Don't give up. You mustn't, you can't give up,” he said. “All it takes for evil to triumph is for good people to do nothing. Therefore, don't do nothing.”