Alexei Navalny, Russia’s best-known opposition leader, is suffering from a mysterious ailment while in prison, which may be the result of a slow-acting poison, as his body weight dropped 8kg in about two weeks, the representative of Kira Jarmis.

“We are not ruling out the fact that right now Alexei Navalny is being slowly poisoned, slowly murdered in order to garner less attention,” Yarmish said in a tweet.

“He is being held in a punishment cell, in acute pain without medical help,” he said.

Replica of Navalny’s cell as presented at an exhibition in Paris

Yarmish said that because of Navalny’s mysterious ailment, emergency services were called Friday night into Saturday to the IK-6 maximum security prison colony in Melekovo, about 250 kilometers east of Moscow, where the dissident is being held.

In 2020, Navalny survived an apparent attempt to poison himself during a flight in Siberia with a nerve agent, tests by Western laboratories revealed. Russia denies that the state tried to assassinate him.

He was hospitalized in Germany to treat the poisoning but voluntarily returned to Russia in 2021, where he was arrested on arrival and jailed for fraud, which Navalny says is politically motivated.