Lyudmila Navalnaya, the mother of opposition leader Alexei Navalny, said that she is resisting pressure from Russian authorities to hold a secret burial for her deceased son.

In a video statement, the elder Navalnaya said investigators have allowed her to see her son's body in a city morgue.  

"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."

On Thursday, imprisoned opposition activist Vladimir Kara-Murza stated that a government-backed assassination team was responsible for killing political leaders opposed to the Kremlin and President Vladimir Putin, according to a video posted on social media.

The British-Russian citizen is currently serving a 25-year sentence for treason at Penal Colony No. 7 in Siberia. 

The comments came as he appeared at a court hearing by way of a video link in a complaint against Russia's Investigative Committee for what he says were two attempts to poison him.

He also claims the authorities did not properly investigate his claims.  He is but one of many opposition figures who have been jailed, killed, or forced to flee the country.

Kara-Murza was convicted of criticizing the invasion of Ukraine and was jailed as part of a crackdown against critics of the war and proponents of free speech. Kara-Murza says the attempts to poison him took place in 2015 and 2017. His wife said doctors confirmed he was poisoned. 

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

On Monday, Ilya Yashin, an opposition figure serving 8 1/2 years in prison for criticizing Russia's war in Ukraine, alleged in a social media post shared on his behalf that Putin had killed Navalny.

"I have no doubt that it was Putin. He's a war criminal," 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 and has denied complicity in the death of Navalny as well.