German doctors treating Russian opposition leader Alexei Navalny for a suspected poisoning said Friday the dissident is still in an induced coma, but his condition is stable and his symptoms are improving.
Navalny, a politician and corruption investigator who is one of Russian President Vladimir Putin's fiercest critics, fell ill on a flight to Moscow from Siberia about a week ago and was taken to a hospital in the Siberian city of Omsk after the plane made an emergency landing.
Last weekend, he was transferred to the Charité hospital in Berlin, where doctors found indications of "cholinesterase inhibitors" in his system.
Found in some drugs, pesticides and chemical nerve agents, cholinesterase inhibitors block the breakdown of a key chemical in the body, acetycholine, which transmits signals between nerve cells.
Navalny, 44, is being treated with the antidote, atropine. According to a statement from Charité, "there has been some improvement in the symptoms caused by the inhibition of cholinesterase activity."
"While his condition remains serious, there is no immediate danger to his life," the hospital said. "However, due to the severity of the patient's poisoning, it remains too early to gauge potential long-term effects."
Navalny's wife, Yulia, has been visiting him regularly in the hospital, and Charité said his doctors "remain in close contact" with her.
Russian doctors dispute Berlin hospital's findings
Navalny's allies insist he was deliberately poisoned and say the Kremlin was behind it, accusations that Russian officials rejected as "empty noise."
Western experts have cautioned that it is far too early to draw any conclusions about what may have caused Navalny's condition, but note that Novichok, the Soviet-era nerve agent used to poison former Russian spy Sergei Skripal and his daughter in Britain, was a cholinesterase inhibitor.
The Russian doctors who treated Navalny in Siberia have repeatedly contested the German hospital's conclusion, saying they had ruled out poisoning as a diagnosis and that their tests for cholinesterase inhibitors came back negative.
Many countries have pushed Russia to investigate the case, something that German Chancellor Angela Merkel said Friday should be done in "full transparency."
Merkel pushes for clarity on events
Navalny was brought to Germany for treatment after Merkel personally offered the possibility of him being treated in Berlin.
"We have an obligation to do everything so that this can be cleared up," Merkel told reporters at her annual summer news conference.
LISTEN | The suspected poisoning of Russian dissident Alexei Navalny:
"It was right and good that Germany said we were prepared ... to take in Mr. Navalny. And now we will try to get this cleared up with the possibilities we have, which are indeed limited."
When there is more clarity about what happened, Germany will try to ensure a "European reaction" to the case, Merkel said.
She cited the poisoning of Skripal and his daughter in Britain two years ago, which prompted many European countries to expel Russian diplomats.
'Russia must contribute' to investigation
Following a meeting in Berlin with his counterparts from 26 European Union countries, Foreign Minister Heiko Maas said Germany had garnered "a lot of recognition" from its partners for taking in Navalny and they had agreed to consult closely on the matter.
He said forcefully that Russia had an obligation to carry out a thorough investigation, something many countries have called for.
"Russia must contribute more to clearing up the Navalny case, and the investigations that we expect must not remain a fig leaf," Maas told reporters.
"The background to this act must be investigated comprehensively and transparently, and those responsible — directly and indirectly — brought to account."
So far, Russian authorities appear reluctant to investigate the politician's condition.
Navalny's team submitted a request last week to Russia's Investigative Committee, demanding authorities launch a criminal probe on charges of an attempt on the life of a public figure and attempted murder, but said there was no reaction.
Kremlin spokesperson Dmitry Peskov said he saw no grounds for a criminal case until the cause of the politician's condition was fully established.
Russia's Prosecutor General's office said Thursday that a preliminary inquiry launched last week hasn't found any indication of "deliberate criminal acts committed against" Navalny.