Verzilov, who runs an online news portal with close ties to punk protest group Pussy Riot, was flown to Germany for urgent treatment after falling ill two weeks ago in Moscow.

“They agree that it was a specially projected poison,” Verzilov told Reuters in an interview in a central Berlin flat.

He said the doctors still had not identified the substance that had poisoned him.

“We think that the whole idea of the attack in Africa, it being a kind of warning, is the most plausible position here.”

Ten days ago, doctors at Berlin’s Charite hospital said he was suffering from anti-cholinergic syndrome, a condition in which the passage of certain neurotransmitters is blocked, the sudden onset of which was strongly indicative of poisoning.

“It is highly probably that he was poisoned,” said Kai-Uwe Eckardt, the doctor treating him.

Verzilov had been working with the three reporters, affiliated with the TsUR online news outlet, who were ambushed and killed on July 30 as they investigated the activities of clandestine Russian private military contractors known as the Wagner Group.