The mother of Russian opposition leader Alexei Navalny appealed Tuesday to President Vladimir Putin to intervene and turn her son’s body over to her so she can bury him with dignity.

Lyudmila Navalnaya, who has been trying to get his body since Saturday, appeared in a video outside the Arctic penal colony where Navalny died on Friday.

“For the fifth day, I have been unable to see him. They wouldn’t release his body to me. And they’re not even telling me where he is,” a black-clad Navalnaya said in the video, with the barbed wire of Penal Colony No. 3 in Kharp, about 1,900 kilometers (1,200 miles) northeast of Moscow.

“I’m reaching out to you, Vladimir Putin. The resolution of this matter depends solely on you. Let me finally see my son. I demand that Alexei’s body is released immediately, so that I can bury him like a human being,” she said in the video, which was posted to social media by Navalny’s team.

Russian authorities have said the cause of Navalny’s death is still unknown and refused to release his body for the next two weeks as the preliminary inquest continues, members of his team said.

They accused the government of stalling to try to hide evidence. On Monday, Navalny’s widow, Yulia, released a video accusing Putin of killing her husband and alleged the refusal to release his body was part of a cover-up.

“They are cowardly and meanly hiding his body, refusing to give it to his mother and lying miserably,” she said.

Lyudmila Navalnaya and her son’s lawyers went to law enforcement agencies and the morgue where the body is believed to be held in the Arctic region, but were unable to get them to turn it over or say where it is.

Kremlin spokesman Dmitry Peskov rejected the allegations of a cover-up, telling reporters that “these are absolutely unfounded, insolent accusations about the head of the Russian state.”

Putin hasn’t commented publicly on Navalny’s death. On Monday, he signed a decree promoting a number of law enforcement and military officials, including Valery Boyarinev, the first deputy chief of the State Penitentiary Service. Boyarinev, who received the rank of colonel-general, has been accused by Navalny’s team of personally ordering restrictions on the opposition leader.

Peskov denied there was any connection between Navalny’s death and the new rank for Boyarinev.

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 Putin another six years in power. Many Russians had seen Navalny as a rare hope for political change amid Putin’s unrelenting crackdown on the opposition.

In her Monday video, Yulia Navalnaya vowed to continue his fight against the Kremlin. On Tuesday, her account on X, where she had posted the video, was briefly suspended by the platform without explanation but later restored.

In a speech Monday to the European Union’s Foreign Affairs Council, she urged EU leaders not to recognize the results of next month’s election, to sanction more Putin allies and to help Russians who flee the country. A copy of her remarks was released Tuesday by Navalny spokeswoman Kira Yarmysh.

The White House said it is preparing additional “major sanctions” on Russia in response to Navalny’s death, with National Security Council spokesman John Kirby saying the new package would be unveiled Friday. He declined to detail them or share how they would expand on the already stiff measures the U.S. and its allies have put on Russia.

Kirby said only that the sanctions, which coincide with the second anniversary of Russia’s invasion of Ukraine, will be “specifically supplemented with additional sanctions regarding Mr. Navalny’s death.”

Navalny, 47, was imprisoned since January 2021, when he returned to Moscow after recuperating in Germany from a nerve agent poisoning he blamed on the Kremlin. He received three prison terms since then, on charges he rejected as politically motivated.

Josep Borrell, the European Union’s foreign policy chief, called for an international investigation of Navalny’s death, but Peskov said the Kremlin would not agree to such a demand.

Since 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 Navalny. Police removed the flowers at night, but more keep appearing.

Peskov said police were acting “in accordance with the law” by detaining people paying tribute to Navalny.

Over 60,000 people have submitted requests to the government asking for Navalny’s remains to be handed over to his relatives, OVD-Info said.

After the last verdict that resulted in a 19-year term, Navalny said he understood he was “serving a life sentence, which is measured by the length of my life or the length of life of this regime.”

In Monday’s video, his widow said: “By killing Alexei, Putin killed half of me, half of my heart and half of my soul.”

“But I still have the other half, and it tells me that I have no right to give up. I will continue the work of Alexei Navalny,” Yulia Navalnaya said.