Omsk (Russia) (AFP) -
The wife of the hospitalised Russian opposition leader Alexei Navalny made a direct appeal to President Vladimir Putin on Friday to allow her husband to be evacuated to Germany, as Russian doctors denied he had been poisoned.
Navalny, a 44-year-old lawyer and anti-corruption campaigner who is among Putin's fiercest critics, was in a coma in intensive care in the Siberian city of Omsk after he lost consciousness while on a flight and his plane made an emergency landing on Thursday.
Aides say they believe he was poisoned and that something was put in his tea at an airport cafe.
Navalny's supporters organised an air ambulance with specialists from a German clinic that arrived at Omsk airport but Russian doctors said his condition was too 'unstable' to move him.
His wife Yulia Navalnaya posted on Navalny's Twitter account a letter addressed to Putin, saying: 'I officially apply to you with a demand for permission to take Alexei Navalny to Germany.'
Kremlin spokesman Dmitry Peskov said there were 'no obstacles' to evacuating Navalny and this was 'purely a medical decision'.
Russian doctors treating Navalny said tests had shown no trace of any poison and suggested he lost consciousness due to low blood sugar.
'So far no poison has been identified in the blood and urine,' Anatoly Kalinichenko, the deputy head doctor of the hospital, told journalists in Omsk.
'We do not believe that the patient suffered poisoning,' he said.
The hospital's chief doctor Alexander Murakhovsky said the preliminary diagnosis was a 'metabolic disorder'.
This could have caused a 'sharp drop in blood sugar in the plane that led to loss of consciousness,' he said.
Navalny's wife Yulia told journalists: 'We certainly can't trust this hospital.'
She said she wanted to 'treat him in an independent hospital, whose doctors we trust.'
The German doctors had been allowed to see him, Navalny's aide Leonid Volkov told reporters at a press conference in Berlin.
The German government said it was in touch with the Russian authorities over the 'humanitarian emergency'.
- 'Play for time' -
Navalny's spokeswoman Kira Yarmysh claimed Russia's refusal to evacuate Navalny was a ploy to 'play for time' and make it impossible to trace poison, posing a 'critical threat to his life'.
The director of Navalny's Anti-Corruption Foundation, Ivan Zhdanov, said a police officer told him they had detected a poison that was 'dangerous not only to Alexei but to those around him', without saying where this was found.
The air ambulance dispatched by a German charity to bring Navalny to Berlin for treatment landed in Omsk after Chancellor Angela Merkel extended an offer of treatment.
European Union leaders including Merkel and French President Emmanuel Macron have voiced concern for Navalny, who has faced repeated physical attacks and prosecutions in more than a decade of opposition to Russian authorities.
The EU spokesperson for foreign affairs and security policy, Nabila Massrali, said: 'The Russian authorities are well aware we are closely watching this,' citing the need for 'his safe transfer and treatment.'
The US embassy in Moscow said in a tweet that if the poisoning claim proved true it would represent 'a grave moment for Russia, and the Russian people deserve to see all those involved held to account'.
Navalny lost consciousness shortly after his plane took off on Thursday from Tomsk in Siberia, where he was working to support opposition candidates ahead of regional elections next month.
Yarmysh said he had seemed 'absolutely fine' before boarding the flight and had only consumed a cup of tea at the airport.
She said she was sure he had suffered from an 'intentional poisoning' and put the blame on Putin.
Peskov said claims of poisoning were 'only assumptions' unless tests proved otherwise.
Navalny has made many enemies with his anti-corruption investigations, which often reveal the lavish lifestyles of Russia's elite and attract millions of views online.
- Previous poisonings -
He has suffered physical attacks in the past, including a 2017 incident where he endured chemical burns to his eye after green dye was splashed on his face.
Last year Navalny said he suspected poisoning when he suffered rashes and his face became swollen while serving a short jail term after calling for illegal protests.
He has been the target of multiple criminal probes and spent numerous stretches in police cells for organising illegal protests, while his Anti-Corruption Foundation was regularly raided by police and investigators.
The latest incident follows several infamous poisonings of Kremlin critics in the past.
Britain named two Russian spies as suspects after Russian double agent Sergei Skripal and his daughter Yulia were poisoned with the nerve agent Novichok in the city of Salisbury in March 2018.
Former Russian security service agent Alexander Litvinenko was fatally poisoned with radioactive polonium in a cup of tea in London. Russia refused to extradite chief suspect Andrei Lugovoi, who became a nationalist MP after the 2006 attack.
Several other opposition figures have suffered severe illnesses in Russia that they blamed on poisoning.