Police in Russia have detained hundreds of people protesting against the death of opposition leader Alexei Navalny in an Arctic prison.

OVD-Info, a Russian human rights group, said that more than 200 people had been arrested, including a priest, in one of the largest nationwide outbreaks of protests since a mobilisation order in September 2022.

The police response to the protests of support for Navalny appeared uneven, with reports of mass arrests in St Petersburg but a softer stance in Moscow and other cities. The Kremlin has outlawed anti-Kremlin protests and OVD-Info said that police were tracking protesters.

“The security forces in several cities are taking data from people who come to lay flowers in memory of Alexei Navalny,” it said.

Impromptu memorials to Navalny bearing candles, flowers and portraits sprung up in most Russian cities. One photo of a memorial published on Telegram referenced the dozens of other Russian opposition activists also in prison.

“My Russia sits in prison,” it said. Another quoted Navalny as saying that there would be “no surrender” to the Kremlin.

But Kremlin officials dismantled many of these memorials as quickly as they appeared. Video posted on Telegram showed hooded men pulling up red carnations and dumping them in rubbish bags.

Police in riot gear also cordoned off memorials to Soviet repression that were being used by mourners to express their support for Navalny.

Although the death of 47-year-old Navalny was splashed across newspapers around the world on Saturday morning, Russian state media largely ignored it.

This, analysts said, was part of the Kremlin’s strategy to minimise the fallout from the death of one of Vladimir Putin’s most dangerous opponents one month before a presidential election.

Russian prison officials said that Navalny had died after falling ill during a short walk on Friday at an Arctic penal colony. Although the cause of death has not been verified, Navalny’s colleagues in exile have confirmed that their leader has died.

“Navalny was killed,” said Maria Pevchikh, chairwoman of Navalny’s Anti-Corruption Foundation. “Alexei will live for ever in millions of hearts, in our thoughts and memories.”

Anti-corruption group

A prison doctor said that Navalny had died of a blood clot and could not be revived but a lawyer for Navalny’s anti-corruption group said that the cause of death could not be established.

Navalny’s mother also said that she had not been able to find her son’s body, which they had been told was in a morgue in Salekhard, near the IK-3 prison colony where he died.

“It was closed, despite the prison saying that it was open and Navalny’s body was there,” Navalny’s team said on Telegram.

In the West, leaders have accused the Kremlin of murdering Navalny, who had been sentenced to three decades in prison for various financial and extremism crimes that his supporters said were concocted in revenge for leading anti-Kremlin protests.

Lord Cameron, the Foreign Secretary, said that the people responsible for the death of Navalny should be punished. “There should be consequences where appalling human rights outrages like this take place,” he said.