The German hospital treating Russian opposition leader Alexei Navalny has said he has been taken out of an induced coma and is responsive.

Mr Navalny, a fierce critic of Russian president Vladimir Putin, was flown to Germany on August 22, two days after falling ill on a domestic flight in Russia.

German chemical weapons experts say tests show that 44-year-old Mr Navalny was poisoned with a Soviet-era nerve agent, prompting the German government last week to demand that Russia investigate the case.

Berlin’s Charite hospital said on Monday that Mr Navalny’s condition has improved, allowing doctors to end the medically induced coma and gradually ease him off mechanical ventilation. It noted that he was responding to speech but “long-term consequences of the serious poisoning can still not be ruled out”.

He has been in an induced coma in the Berlin hospital since he was flown to Germany for treatment.

German authorities said last week that tests showed “proof without doubt” that he had been poisoned with a chemical nerve agent from the Novichok group. British authorities identified the Soviet-era Novichok as the poison used on former Russian spy Sergei Skripal and his daughter in 2018.

Earlier, chancellor Angela Merkel’s office indicated she might be willing to rethink the fate of a German-Russian gas pipeline project in a sign of Berlin’s growing frustration at Moscow’s stonewalling over the poisoning of Mr Navalny.

German Chancellor Angela Merkel
German Chancellor Angela Merkel (Markus Schreiber/Pool/AP)

Germany’s foreign minister Heiko Maas said in an interview on Sunday that the Russian reaction could determine whether Germany changes its long-standing backing of the Nord Stream 2 pipeline.

“The chancellor also believes that it’s wrong to rule anything out,” Mrs Merkel’s spokesman Steffen Seibert told reporters after being asked about Mr Maas’s comments.

Previously, Mrs Merkel had insisted on “decoupling” the Navalny case from the pipeline project, which the US strongly opposes.

In early August, three Republican senators threatened sanctions against the operator of a Baltic Sea port located in Mrs Merkel’s parliamentary constituency over its role as a staging post for ships involved in building Nord Stream 2.