Doctors treating Russian opposition politician Alexei Navalny in a German hospital say tests indicate he was poisoned.
Medics at the facility in Berlin, where the Putin critic was transferred to from Omsk in Russia’s Siberia region on Saturday, said: “The clinical findings indicate intoxication by a substance from the cholinesterase inhibitor group.
“The specific substance has not been identified so far and a further wide-ranging analysis has been initiated.
“The effect of the toxin, i.e. the cholinesterase inhibition in the organism, has been proven several times and in independent laboratories.”
They said the Russian dissident remains in an artificial coma and is in a serious condition at the Charite hospital “but there is currently no acute danger to his life”.
German Chancellor Angela Merkel has since called on Russian police to “investigate this crime in detail and in full transparency”.
“Those responsible must be identified and held accountable,” she added.
Mr Navalny, 44, fell ill and collapsed last Thursday on an internal Russian flight from Tomsk in Siberia to Moscow after drinking what his supporters suspect was poisoned tea.
Doctors in Germany said the Russian opposition leader is being treated with atropine but they cannot currently determine whether he will have lasting issues, “especially in the area of the nervous system”.
Atropine is used to treat certain types of nerve agent and pesticide poisonings, as well as some types of slow heart rate and to decrease saliva production during surgery.
Cholinesterase inhibitors are a group of chemicals that prevent the breakdown of acetylcholine, which then builds up and causes a jam in the nervous system.
Mr Navalny’s doctors in Siberia had said he was too unstable to be moved, despite a team of German specialists in a medical plane being sent to help.
The politician’s supporters believe medics were stalling until any poison in his system could no longer be detected.
The Kremlin denies its resistance to the transfer was political and says it was purely a medical decision.
Doctors in Omsk said Mr Navalny was not poisoned, suggesting a drop in blood sugar may have caused him to lose consciousness.
Police have been posted outside the hospital in Berlin since the Russian politician’s arrival as a “precaution”, Dirk Wiese, the German government’s co-ordinator for Eastern European affairs said.
“The circumstances of what led to Alexei Navalny’s critical condition haven’t yet been clarified,” he said.
“We expect full transparent and also cooperative clarification, especially from the Russian authorities.
“And before it is known how this happened, appropriate security precautions are necessary.”