German doctors have confirmed Russian anti-corruption activist Alexei Navalny was poisoned.
Mr Navalny fell ill in Russia on Thursday and was transferred to Berlin's Charité university hospital on Saturday, where he remains in a serious but non-life-threatening condition.
“The clinical tests indicate an intoxication through a substance from the cholinesterase active ingredient group,” said the hospital in a statement. “The specific substance has not been identified so far, and a further wide-ranging analysis has been initiated.”
Cholinesterase is an enzyme, found especially in the heart, brain and blood, required to avoid overstimulation of the nervous system. It can be affected by genetic factors and by poisoning. The Charité statement added that the effect of the detected toxin “has been proven several times and in independent laboratories”.
Mr Navalny is being treated with an antidote – atropine – but the hospital said his clinical outcome remained unclear. Effects on his nervous system are possible, the statement added. Mr Navalny remains in an induced coma, under tight security, at the city centre facility, visited only by his wife and a small circle of supporters.
"The decisive question is whether he survives this undamaged and can take up his role again," said Jaka Bizilj, chairman of the German foundation that organised the private jet to transport Mr Navalny to Berlin. "If he survives this undamaged, what we all hope, then he is certainly out of political battle for one, two months."
Supporters of Mr Navalny believe he unwittingly drank poison-laced tea.
‘Low blood sugar’
Russian doctors had suggested the long-time opponent of President Vladimir Putin was suffering from a metabolic disease possibly caused by low blood sugar. Later, health officials in Russia suggested an industrial chemical used in polymers had been found on Mr Navalny's skin and hair.
Mr Navalny was transferred to Germany after a prolonged battle between his family and Russian doctors.
German chancellor Angela Merkel intervened in the standoff to offer Germany's assistance. Her spokesman on Monday said the Russian activist was "with a certain degree of probability, poisoned".
"The suspicion is not that Mr Navalny seriously poisoned himself but that someone seriously poisoned Mr Navalny," said Steffen Seibert, the chancellor's spokesman, on Monday. "Unfortunately in the recent past there has been one or other exemplary cases."
Mr Navalny (44) had been on a tour of Siberia and was on a return flight to Moscow on Thursday when he fell ill. The flight was diverted to the city of Omsk, where he was rushed to a local hospital.
Berlin’s Charité hospital has a history of treating Russian dissidents.
In 2018 opposition activist Pyotr Verzilov, an associate of the Russian punk rock band Pussy Riot, was treated in the Berlin clinic for a suspected poisoning.
Pressure is growing on Dr Merkel to take a tougher line on Russia. A year ago a Chechen separatist living in Berlin was shot dead in a city centre park in what federal authorities say was a contract killing ordered by the Kremlin. Mr Putin later insisted the man was responsible for the deaths of 98 people in the March 2010 Moscow Metro attacks.