MOSCOW: A scientist involved in the secret Soviet programme to create the Novichok nerve agent has apologised to the Russian opposition politician Alexei Navalny, who is recovering from poisoning in Berlin.

Vil Mirzayanov, a chemist who was the first to reveal Novichok's development, in an interview with Russia's TV Rain on Saturday evening said he wanted to apologise to Navalny after Germany said it found "unequivocal evidence" he was poisoned with Novichok.

The opposition politician on Saturday described his severe symptoms after falling ill on a plane on August 20, including inability to form words, saying he still struggled to pour a glass of water or use a phone.

"I offer my profound apologies to Navalny for the fact that I took part in this criminal business, developing this substance that he was poisoned with," said Mirzayanov, who now lives in the United States and wrote the first articles on Novichok's development in the early 1990s.

His apology comes as another scientist who worked on the programme has denied that Navalny could have been poisoned with Novichok.

So far three scientists, now in their 70s, have made public statements after working on the top-secret Soviet project.

Mirzayanov predicted that Navalny would eventually recover.