International condemnation has cascaded on Russia after the German government said on Wednesday that tests conducted on Alexei Navalny showed the Putin critic had been attacked with the nerve agent Novichok.
The EU, NATO and several Western governments have called for an explanation from Moscow following the German findings. Russia has stonewalled, accusing Berlin of failing to share evidence.
Toxicological tests using samples from Navalny had revealed "unequivocal proof of a chemical nerve agent from the Novichok group", a statement released by Chancellor Angela Merkel's spokesperson stated.
The nerve agent was developed by the Soviet Union during the Cold War and is banned under the Chemical Weapons Convention of 1997.
Merkel condemns 'attempted murder'
"It is shocking information about the attempted murder by poison of one of Russia's leading opposition members," said Merkel in a later news conference.
"This means that Alexei Navalny is a victim of a crime," Merkel added. "It was an attempt to silence him. I condemn this in the strongest possible terms on behalf of the entire German government."
“There are very serious questions now that only the Russian government can answer, and must answer,” she added.
The Charité hospital in Berlin, where the dissident is being treated, released a statement saying that following this "confirmed poisoning" Navalny's condition is improving but remains serious.
"The reason for this improvement is the gradual recovery of cholinesterase activity. Alexei Navalny continues to be treated in an intensive care unit and remains on a ventilator. Recovery is likely to be lengthy. It is still too early to gauge the long-term effects which may arise in relation to this severe poisoning," the statement said.
Navalny fell ill during an August 20 flight from Siberia to Moscow and entered into a coma.
Doctors in the Siberian city of Omsk, where Navalny was initially treated, refuted his staff's accusation that he had been poisoned, suggesting instead that he had suffered from a glycemic imbalance.
German doctors, who were first refused access to the prominent opposition figure, were eventually allowed to fly him to Berlin on August 22.
Russia called on to 'explain itself'
"It is a shocking event that Alexei Navalny was the victim of an attack with a chemical nerve agent in Russia," the German government's statement added.
"The federal government condemns this attack in the strongest possible terms. The Russian government is urged to explain itself," it went on.
German Foreign Minister Heiko Maas has asked the Russian ambassador in Germany to inform him of their findings and to "request that the background to the now proven poisoning of Alexei Navalny be fully explained in full detail and in full transparency." His comments came at a press conference held after the release of the statement that the federal government issued.
"We now know that there was an attack with a chemical nerve agent. This makes it all the more urgent that those responsible in Russia are also identified and brought to justice."
"Russia should be interested in having a good relationship with its European neighbours and now is the time to provide a crucial contribution to this," he added.
Germany also said that it will discuss the matter with its European Union and NATO partners in order to work on "an appropriate joint reaction".
Western leaders echo Germany's call
Russia immediately endured a barrage of similar calls from Western countries and institutions.
"I utterly condemn the use of a military-grade nerve agent, which makes it even more urgent that Russia conducts full & transparent investigation," tweeted NATO Secretary General Jens Stoltenberg.
European Commission President Ursula von der Leyen tweeted that the nerve agent attack was a "despicable and cowardly act", calling for the perpetrators to be brought to justice.
The EU's chief diplomat Josep Borrell said in a statement that the tests proved "Mr Navalny was poisoned by a military-grade chemical nerve agent... developed by the Soviet Union and later, Russia". He added that the use of chemical weapons was "completely unacceptable and a breach of international law".
Heiko Maas' British counterpart, Dominic Raab, said it was “absolutely unacceptable that this banned chemical weapon has been used again". He added that “the Russian government has a clear case to answer” and “must tell the truth about what happened to Mr Navalny".
British Prime Minister Boris Johnson tweeted that it was "outrageous that a chemical weapon was used against Alexey Navalny", calling for an explanation from Russia and vowing to "work with international partners to ensure justice is done".
There was similar condemnation from France. Expressing his "consternation" at Germany's confirmation of the use of Novichok to poison the Russian dissident, Foreign Minister Jean-Yves Le Drian castigated "the shocking and irresponsible use of such an agent" which he said contravened international agreements.
Italy's Foreign Ministry also "condemned with force" the poisoning which it described as a "crime", expressing its "profound concern and indignation" and calling for clarification from Moscow.
After the initial signs that the Putin critic had been poisoned, there were numerous calls from Western leaders -- including Merkel, Boris Johnson and US Secretary of State Mike Pompeo -- for Russia to investigate.
'Nothing to reply to', says Moscow
The Russian Foreign Ministry appeared reluctant to comment on the accusations on Wednesday. Spokeswoman Maria Zakharova instead blamed Germany for not sharing "a single material" with Russian authorities.
"We don't have anything to reply to," she said, adding that the Navalny case had "nothing to do with medical scientific research... it's simply a political story".
Kremlin Press Secretary Dmitry Peskov earlier told the TASS news agency that the Russian government had for now received no information from German authorities on their investigations.
The Kremlin has previously rejected suggestions that Navalny was poisoned by Russian authorities, describing the claims as "empty noise".
Leonid Volkov, a top aide of Navalny, posted on Twitter: "In 2020, poisoning Navalny with Novichok is exactly the same as leaving an autograph at a crime scene". His post included a picture of Russian President Vladimir Putin's name and signature.
Interfax said Russian doctors had already concluded in their own investigation that Navalny was suffering from chronic pancreatitis.
Western countries have accused Russia of using Novichok to poison former Russian spy Sergei Skripal and his daughter in the British city of Salisbury in March 2018. Both survived the attack but another person, Dawn Sturgess died after being exposed to the poison.