Russian investigators will keep Alexei Navalny's body for "at least two weeks" to examine the corpse, his spokesperson said Monday, describing it as a ploy by the authorities.

Russia reported Navalny's death on Friday and his mother has been denied access to the body, enraging supporters who have accused authorities of trying to cover up Navalny's "murder".

"Investigators told Alexei's mother and lawyers that they are not handing over the body and in the next 14 days they will conduct a chemical analysis, an investigation," Navalny spokesperson Kira Yarymsh said in a YouTube broadcast.

"For at least two weeks they will do some kind of inspection," she said.

"I'll say it again: Navalny's body is being hidden to hide the traces of the murder. This 14-day 'chemical analysis' is an outright lie and mockery," she said in a subsequent statement on social media site X, the former Twitter.

Navalny's mother, Lyudmila, flew to the Arctic prison colony where her son was being held on Saturday, but has been blocked from accessing the morgue where she was told his body was.

Earlier Monday, the Kremlin said an investigation into Navalny's death was ongoing and that there were "no results" as of yet. 

President Vladimir Putin's spokesperson Dmitry Peskov said the Kremlin would not decide what happens to the body or when it is released.

Navalny's wife, Yulia Navalnaya, said on Monday: "Putin killed my husband."

The opposition leader's spokesperson said she expected authorities to hold Navalny's body beyond the 14-day period.

Yarymsh and Navalnaya drew comparisons with what happened in 2020, when Navalny fell seriously ill while on a flight to Moscow, and doctors tried to block him being evacuated to Europe for specialist treatment.

Navalnaya eventually secured his release, taking her husband on a medical plane to Germany where tests revealed he had been poisoned with a military-grade nerve agent.