Doctors in Berlin Monday confirmed prominent Kremlin critic Alexei Navalny was poisoned. Navalny was evacuated from Russia for evaluation at Charité Hospital after he became severely ill during a Thursday flight from Siberia to Moscow.

Navalny, 44, had consumed a drink at an airport café, according to a spokesperson for the opposition leader.

Navalny’s staff and other critics of Russian President Vladimir Putin’s government asserted the politician was a victim of a state-ordered assassination attempt. Western intelligence operations have frequently linked attempted or successful poisonings to the Russian government, making it close to a tell-tale sign of state-sanctioned activity.

“It was clear after his arrival that security measures had to be put in place because we are dealing with a patient who was likely the target of a poison attack,” said Steffen Seibert, a spokesman for the German government.

Doctors have not been able to determine conclusively what substance was used on Navalny, but Charité Hospital said in a statement that it is suspected to be a cholinesterase inhibitor, which blocks the proper function of the nervous system. This same sort of nerve agent was used against ex-Russian-spy Sergei Skripal and his daughter in 2018.

Navalny is being kept in a medically induced coma and treated with Atropine. The hospital confirmed his life is not in “acute danger.” When initially examined in Omsk, Russian doctors concluded that there were no signs Navalny had been poisoned, prompting speculation of a cover-up. These physicians also reportedly tried to prevent Navalny’s evacuation to Berlin, citing pressure from the Russian government.

Kremlin critic Alexei Navalny has been jailed a number of times by Russian authorities
Kremlin critic Alexei Navalny has been jailed a number of times by Russian authorities AFP / Vasily MAXIMOV