The mother of Alexei Navalny, the Putin critic who died in a Russian prison, has called on President Vladimir Putin to release his body.
In a video filmed outside the colony where he died on Friday, she said she had been trying to see him for five days but didn't even know where he was.
And Navalny's wife Yulia urged the authorities not to stop his loved ones from saying goodbye to him.
The family have been told his body will not be released for two weeks.
His mother was informed it was being held for "chemical analysis", a representative for Navalny said.
There has been no confirmation of the whereabouts of the body from Russian authorities, while efforts to locate it have been repeatedly shut down.
Yulia Navalnaya has alleged her husband's body was being kept until traces of poisoning by the nerve agent Novichok had disappeared. Navalny survived an attempt to kill him using the poison in 2020.
Kremlin spokesman Dmitry Peskov called the accusations "unfounded and vulgar", but added that since Ms Navalnaya was widowed just days ago he wouldn't comment further.
Navalny's mother made a direct appeal to President Putin outside the Siberian penal colony known as Polar Wolf, where his death was announced on 16 February.
"I've not been able to see him for five days, they're refusing to give his body to me, and they're not even saying where he is," she says.
"I'm asking you, Vladimir Putin - it all depends on you alone. Let me finally see my son. I demand that Alexei's body is released immediately so I can give him a decent burial."
Her words were echoed in a strongly worded post on X (formerly known as Twitter) by her daughter-in-law.
"I couldn't care less about how the murderer's press secretary comments on my words," she said, referring to Mr Peskov. She has directly accused Mr Putin of killing her husband.
"Give back Alexei's body and let him be buried with dignity, don't get in the way of people saying goodbye to him," she said.
Her remarks follow speeches to the European Union and the Munich Security Conference, and an emotional video released on Monday where she vowed to continue her husband's work to fight for a "free Russia".
She also told EU leaders on Monday not to recognise Russia's presidential elections on 16 March and to pursue members of Mr Putin's inner circle who were still trying to dodge sanctions.
Navalny's death in prison was announced on Friday. The authorities at the Siberian penal colony where he was being held said he had never regained consciousness after he collapsed following a walk.
Officials later said that Navalny had suffered "sudden death syndrome".
His mother and lawyer travelled to the remote colony as soon as news of his death broke.
Attempts to locate the body have repeatedly been shut down by the prison mortuary and local authorities.
On Monday, the Kremlin said an investigation into Navalny's death was ongoing and that there were "no results" as of yet.
Later, Navalny's spokeswoman Kira Yarmysh said that investigators had told Navalny's mother Lyudmila they would not hand over the body for two weeks while they conducted a "chemical analysis".
Navalny, who was the Russian opposition's most significant leader for the last decade, had been serving a 19-year sentence on politically motivated charges.
Western leaders have put the blame for Navalny's death squarely on President Putin. Both the EU and the US have said they are considering new sanctions on Russia.
The UK Foreign Secretary, Lord Cameron, has also said he expects Britain and the rest of the G7 group of rich nations to impose fresh sanctions on any Russians involved in the death.
