• Navalny fell ill Aug. 20 on a domestic flight in Russia
  • He initially was treated at a hospital in Siberia, but transferred to Germany Aug. 22
  • German Chancellor Angela Merkel is reported linking a Russian investigation into who poisoned Navalny to the fate of the Nord Stream 2 gas pipeline

German doctors removed Russian opposition leader Alexei Navalny from a ventilator and said Monday he was responsive to “verbal stimuli.” Navalny, a fierce critic of Russian President Vladimir Putin, has been in a medically induced coma since he allegedly was poisoned while traveling in Russia.

Navalny, 44, fell ill Aug. 20 on a domestic flight in Russia. German doctors said he had been poisoned with the Soviet-era nerve agent Novichok. Russian officials have denied poisoning him and initially refused to allow him to be evacuated to Germany for treatment. He was moved to Germany Aug. 22.

"He is responding to verbal stimuli," Charite hospital said in a statement, Deutsche Welle reported. Doctors said his condition had improved, but “it remains too early to gauge the potential long-term effects of his severe poisoning,” Euronews quoted the statement as saying.

German authorities said there was no doubt Navalny had been poisoned with the same agent British authorities identified in the 2018 poisoning of former Russian spy Sergei Skripal and his daughter.

The attack on Navalny may have put the German-Russian Nord Stream 2 gas pipeline in jeopardy, the Associated Press reported.

German Foreign Minister Heiko Maas said Russian reaction to the poisoning evidence could determine the pipeline’s fate, and a spokesman for Chancellor Angela Merkel, who initially didn’t want the poisoning and pipeline linked, said the German leader is not ruling anything out. Merkel has said she expects Russia to investigate who was responsible for the poisoning, which she said raises “very serious questions that only the Russian government can answer and must answer,” Sky News reported.

“I can’t express a clear, time-limited expectation, except that we are certainly not talking about months or the end of the year,” spokesman Steffen Seibert said.

The U.S. has strongly opposed the pipeline, threatening sanctions against the port in Merkel’s home district that is to be used as a staging area.