Russia faced mounting international calls on Tuesday for a probe into the poisoning of opposition leader Alexei Navalny even as the Kremlin dismissed the findings of his German doctors.
The 44-year-old Navalny, who is one of the fiercest critics of President Vladimir Putin and has exposed massive official corruption, is being treated in a Berlin hospital after falling ill on a flight in Siberia last Thursday.
He was treated for two days in a hospital in Siberia before being airlifted to Berlin's Charite hospital, whose doctors said Monday that clinical tests "indicate poisoning with a substance from the group of cholinesterase inhibitors".
These are substances used in nerve agents as well as medicines and insecticides that suppress an enzyme needed for the central nervous system to function normally.
Navalny's supporters claim he was poisoned by a cup of tea he drank at a Siberian airport before a flight to Moscow, pointing the finger of blame at Putin.
But Kremlin spokesman Dmitry Peskov ridiculed accusations of Putin's involvement.
"We cannot take such accusations seriously. These accusations cannot be true at all and are more likely empty noise," he told journalists.
He also accused the German medics of haste in concluding that Navalny was poisoned, saying the toxin responsible for his illness has not been identified.
"We don't understand why our German colleagues are in such a hurry. The substance hasn't yet been established," he said.
Russia has not opened a criminal investigation into the poisoning and Peskov said there was "no pretext" for this until the toxin is identified.
Moscow's foreign ministry attacked Western countries' "suspicious haste" to determine Navalny was poisoned, adding their remarks had been "deeply offensive" to the Russian doctors who first treated him.
- 'Criminal act' -
Peskov's comments came as Western leaders urged Russia to conduct an impartial probe.
In a statement Tuesday, US Secretary of State Mike Pompeo called for "a full and transparent investigation... and for those involved to be held accountable," adding that Washington is "deeply concerned" by the apparent poisoning.
The EU has also urged Russia to hold a "independent and transparent investigation" while German Chancellor Angela Merkel called for those responsible to be held accountable.
The French foreign ministry on Tuesday said it was profoundly concerned over the "criminal act" and urged a "swift and transparent investigation" to bring those responsible to justice.
Navalny is the latest in a long line of Kremlin opponents to fall seriously ill or die from poisoning, either suspected or proven.
The nerve agent Novichok was used against former Russian double agent Sergei Skripal and his daughter Yulia in Britain in 2018. Two Russian military agents identified by Britain as suspects have disappeared from view.
In 2006, former Russian security service agent Alexander Litvinenko died in London after drinking tea laced with radioactive polonium-210. Russia refused to extradite the chief suspect, Andrei Lugovoi.
The Kremlin reaction angered Navalny's allies.
"It was obvious that the crime would not be properly investigated and the criminal found, though we know very well who he is," tweeted his spokeswoman Kira Yarmysh.
"But the particular way Peskov talks about this makes me rage."
- 'Lots of other versions' -
Peskov cast doubt on the German government's statement that Navalny "fairly likely was poisoned," saying there were other possible explanations.
"We can only partially agree... There is a likelihood of something else too."
He acknowledged that poisoning "can be seen as one of the versions, but there are a lot of other medical versions".
Peskov said Russian medics at the hospital in the Siberian city of Omsk had also detected a low level of the cholinesterase enzyme and treated Navalny with the antidote atropine, as the German medics are doing.
The chief toxicologist at the Omsk hospital, Alexander Sabayev said Monday that Navalny tested negative for cholinesterase inhibitors, however.
The Russian doctors earlier suggested that Navalny had a "metabolic disorder" and low blood sugar.
He was attacked in 2017 by pro-Kremlin activists who threw green dye at his face, causing chemical burns to his eye.