Alexei Navalny’s family have been refused access to his body for a third day, his team said, adding that his mother was “not allowed” into a morgue where his remains may be being held.

Russia’s prison service said Navalny died after a walk in his Arctic prison on Friday.

His mother, Lyudmila, travelled to the remote colony on Saturday, but has still not been allowed access to her son’s body.

“Alexei’s mother and his lawyers arrived at the morgue early in the morning. They were not allowed to go in. One of the lawyers was literally pushed out. When the staff was asked if Alexei’s body was there, they did not answer,” said Kira Yarmysh, Navalny’s spokeswoman, on social media.

Russian investigators told the mother of the late opposition leader and his lawyers on Monday that the investigation into his death in prison “has been extended”, Ms Yarmysh added.

“It is not known how long it will continue. The cause of death is still ‘undetermined’. They’re lying, playing for time and do not even hide it,” the spokeswoman said on X, formerly known as Twitter.

The charismatic Navalny was Vladimir Putin’s main political opponent.

His death came three years into his imprisonment in Russia.

He died in the Russian Far North in one of Russia’s harshest prisons after his health had deteriorated for months.

Putin has not yet commented on the death.