Russian opposition leader Alexei Navalny, who Germany says was poisoned by the nerve agent Novichok, is now out of a medically induced coma, a Berlin hospital treating him said on Monday. 

The hospital said the 44-year-old’s condition has improved and is being weaned off mechanical ventilation. “He is responding to verbal stimuli,” Charite hospital said in a statement.

Although the hospital said it was too early to determine the long-term impact of the poisoning. Germany last week said that Russian President Vladimir Putin’s critic Navalny was poisoned by Novichok, a military-grade poison that was developed by the Soviet Union towards the end of the Cold War. 

Navalny fell ill after boarding a plane in Siberia last month and was being treated in a local hospital before being flown to Berlin. 

Germany said last week that toxicology tests have found “unequivocal evidence” that Novichok was used on Navalny, prompting Chancellor Angela Merkel and her Western counterparts to demand answers from Russia. The Kremlin has however denounced attempts to blame the poisoning on Russia as “absurd”.

Novichok, a military-grade poison, can be deployed in an ultra-fine powder, liquid or vapour. It was used against ex-double agent Sergei Skripal in Britain in 2018, a poisoning that the West believes was ordered by the Kremlin.