The mother of Russia’s top opposition leader Alexei Navalny said she has seen her son’s body and that she is resisting strong pressure by authorities to agree to a secret burial outside the public eye.

Speaking in a video statement from the Arctic city of Salekhard, Lyudmila Navalnaya said investigators have allowed her to see her son’s body in the city morgue.

She said she reaffirmed the demand to give Mr Navalny’s body to her and protested against what she described as authorities trying to force her to agree to a secret burial.

“They are blackmailing me, they are setting conditions where, when and how my son should be buried,” she said. “They want it to do it secretly without a mourning ceremony.”

Mr Navalny’s spokesman, Kira Yarmysh, said on X, formerly Twitter, that his mother was also shown a medical certificate stating that the 47-year-old politician died of “natural causes”.

Across the ocean in San Francisco, US President Joe Biden met Mr Navalny’s widow, Yulia Navalnaya, and 20-year-old daughter Dasha and expressed “condolences for their devastating loss”.

Mr Navalny’s “legacy of courage will live on in Yulia and Dasha, and the countless people across Russia fighting for democracy and human rights”, Mr Biden tweeted.

Mr Navalny, Russia’s most well-known opposition politician, suddenly died in an Arctic prison last week, prompting hundreds of Russians across the country to stream to impromptu memorials with flowers and candles.

The Russian authorities have detained scores of them as they seek to suppress any major outpouring of sympathy for Vladimir Putin’s fiercest foe ahead of the presidential election he is almost certain to win.

Mr Navalny’s mother has filed a lawsuit at a court in Salekhard contesting officials’ refusal to release her son’s body.

A closed-door hearing has been scheduled for March 4. On Tuesday, she appealed to Russian President Vladimir Putin to release her son’s remains so that she could bury him with dignity.

In the video released on Thursday, Ms Navalnaya said she had spent nearly 24 hours in the Salekhard office of the Investigative Committee, where officials told her that they have determined the politician’s cause of death and have the paperwork ready, but she has to agree to a secret funeral.

“They want to take me to the outskirts of the cemetery to a fresh grave and say, ‘Here lies your son’. I don’t agree to this. I want you too — to whom Alexei is dear, for whom his death was a personal tragedy — to have the opportunity to say goodbye to him,” she said.

Ms Navalnaya accused the authorities of threatening her: “Looking into my eyes, they say that if I do not agree to a secret funeral, they will do something with my son’s body. Investigator Voropayev openly told me, ‘Time is not on your side, the corpse is decomposing’,” she said, reiterating her demand to release her son’s body “immediately”.

Mr Navalny’s death has deprived the Russian opposition of its best-known and inspiring politician less than a month before an election that is all but certain to give Mr Putin another six years in power.

Many Russians had seen Mr Navalny as a rare hope for political change amid Mr Putin’s unrelenting crackdown on the opposition.

Since Mr Navalny’s death, about 400 people have been detained across in Russia as they tried to pay tribute to him with flowers and candles, according to OVD-Info, a group that monitors political arrests.

Authorities cordoned off some of the memorials to victims of Soviet repression across the country that were being used as sites to leave makeshift tributes to Mr Navalny. Police removed the flowers at night, but more keep appearing.

Earlier today, imprisoned opposition figure Vladimir Kara-Murza urged Russians not to give up after Mr Navalny’s death, and he alleged a state-backed hit squad was taking out the Kremlin’s political opponents, according to a video posted to social media.

A British-Russian citizen, Mr Kara-Murza is serving a 25-year sentence for treason at a penal colony in the Siberian city of Omsk.

His comments came as he appeared via a video link in a court hearing over a complaint against Russia’s Investigative Committee for what he believes were two poisoning attempts against him. He alleges the committee did not properly investigate the attempts.

Mr Kara-Murza is one of several opposition figures who have either been imprisoned, forced to flee the country or killed. He was convicted of criticising Russia’s invasion of Ukraine and was handed a stiff sentence as part of a crackdown against critics of the war and freedom of speech.

“We owe it… to our fallen comrades to continue to work with even greater strength and achieve what they lived and died for,” Mr Kara-Murza said in the video, which was shared by the Russian Sota telegram channel.

Mr Kara-Murza says the attempts to poison him took place in 2015 and 2017. In the first, he nearly died of kidney failure, although no cause was determined. He was admitted to hospital with a similar illness in 2017 and put into a medically induced coma. His wife said doctors confirmed he was poisoned.

Mr Kara-Murza’s latest hearing came after months of postponements. In January, he was moved from another prison in Siberia and placed in solitary confinement over an alleged minor infraction.

According to the video shared by Sota, Mr Kara-Murza alleged there is a “death squad within the Federal Security Service, a group of professional killers in the service of the state, whose task is to physically eliminate political opponents of the Putin regime”.

He said investigative journalists had shown the group of FSB officers participated in his poisoning, as well as Mr Navalny’s poisoning with a nerve agent in 2020 and the surveillance of opposition politician Boris Nemtsov before he was shot and killed in 2015 on a bridge near the Kremlin.

On Monday, Ilya Yashin, an opposition figure serving more than eight years in prison for criticising Russia’s war in Ukraine, alleged in a social media post shared on his behalf that Mr Putin had killed Mr Navalny.

“I have no doubt that it was Putin. He’s a war criminal,” Mr Yashin said. “Navalny was his key opponent in Russia and was hated by the Kremlin. Putin had both motive and opportunity. I am convinced that he ordered the killing.

“I feel a black emptiness inside, he said, adding that he will continue to speak out even though he believes he is also in danger.

The Kremlin has denied any involvement in the illnesses and deaths of the opposition figures, including Mr Navalny.