Gravely ill Kremlin critic Alexei Navalny has been evacuated to Germany for medical treatment, flown out of the Siberian city of Omsk in an ambulance aircraft and taken to a hospital in Berlin.
He is in a coma after drinking what his supporters suspect was poisoned tea; they accuse the authorities of trying to conceal a crime.
Doctors treating him in Omsk had insisted yesterday that he was too ill to be moved.
But they later said his condition was stable enough for the flight. His wife, Yulia, travelled with him.
Navalny's medical evacuation flight - paid for by the German non-governmental organisation Cinema for Peace - landed at Tegel airport in Berlin earlier today. He is being treated at the Charité hospital in the German capital.
The founder of the Cinema for Peace Foundation, activist and filmmaker Jaka Bizilj, told reporters outside the hospital that Navalny's condition was "very worrying".
"It's not only about the question if he will survive this," he said. "It's a question what kind of damage there is, if he will survive this and come back to normal fully."
"We got a very clear message from the doctors that if there had not been an emergency landing in Omsk, he would have died," said Bizilj, adding that it would be up to doctors and Navalny's family to provide further information on his condition.
Bizilj was earlier quoted by Bild tabloid as saying Navalny's condition was stable during the flight and after landing.
Kira Yarmysh, Navalny's spokeswoman, said on Twitter that "This is another proof that nothing was preventing Navalny from being transported, and it was necessary to do so as early as possible."
Yarmysh said it was a pity that doctors had taken so long to approve his flight as the plane and the right documents had been ready since Friday morning.
She tweeted: "Massive thanks to everyone for their support. The struggle for Alexei's life and health is just beginning."
Navalny's personal doctor, Anastasia Vasilieva, was not allowed to see him while he was in hospital in Russia. But she said she was hopeful he could recover now that he was in Germany.
"I'm sure that they can treat him and do everything to eliminate this toxic agent from his body."
Medical staff treating Navalny at the hospital in Omsk said before his flight that his life was not in immediate danger.
Navalny fell ill during a flight from Tomsk to Moscow on Thursday, and his plane made an emergency landing in Omsk.
A photograph on social media appeared to show him drinking from a cup at a Tomsk airport cafe before the flight. His team suspects a poisonous substance was put in his tea.
Disturbing video appeared to show a stricken Navalny howling in agony on the flight. Passenger Pavel Lebedev said he had heard the activist "screaming in pain".
What the doctors said
The head doctor at the hospital where Navalny was being treated in Omsk, Alexander Murakhovsky, warned that doctors did not recommend flying "but his wife insists on her husband being transferred to a German clinic".
"The patient's condition is stable," deputy chief doctor Anatoly Kalinichenko was quoted as saying by the Interfax news agency.
"As we're in possession of a request from relatives to permit him to be transported somewhere, we have now taken the decision that we do not object to his transfer to another in-patient facility," Dr Kalinichenko said.
Doctors said earlier that no poison had been found in his body, suggesting his condition might be the result of a "metabolic disorder" caused by low blood sugar.
Health officials then indicated that traces of an industrial chemical had been found on his skin and hair. The local interior ministry told the Rapsi legal news agency that the chemical was usually included in polymers to improve their elasticity, but its concentration was impossible to establish.
The doctors in Omsk said yesterday they were ready to share all information they have with the German clinic.
The prominent critic of President Vladimir Putin has consistently exposed official corruption in Russia. He has served multiple jail terms.
What do Navalny's supporters say?
At a news conference in Berlin yesterday, Navalny's aide Leonid Volkov said at first doctors at the hospital had been helping to facilitate his transfer but had abruptly stopped doing so.
"[It was] like something was switched off - like medicine mode off, cover-up operation mode on - and the doctors refused to co-operate any more, refused to give any information even to Alexei's wife," he said.
"The doctors who were helping to do the paperwork to make the transportation of Alexei to Charité possible started to say that he's not any more transportable, he's not any more stable, contradicting themselves."
In 2018, the Cinema for Peace Foundation arranged for the treatment of Pyotr Verzilov - an activist with Russian protest group Pussy Riot - who had symptoms of poisoning.
Verzilov's ex-wife, activist Nadya Tolokonnikova, told BBC News that Navalny's condition resembled the "poisoning" of her ex-husband.
"What German doctors told me after not finding poison in my ex-husband's blood is that the poison disappears in three days. So the Russian doctors only let him go when they were sure there was no traces of poison left," she explained.
She also expressed surprise about what has happened to Navalny: "I thought Alexei was so powerful as a political figure that Mr Putin would not interfere."
Navalny's wife, Yulia, wrote to President Putin asking him to allow her husband to be moved. She feared the Russian authorities were stalling so that evidence of any chemical substance would be lost.
Putin's spokesman Dmitry Peskov said on Friday that the Kremlin would help move Navalny abroad if necessary and wished him a "speedy recovery". The following day he said it was purely a medical decision.
Foreign leaders including Germany's Angela Merkel and France's Emmanuel Macron have expressed concern for Navalny.
In the US, Democratic presidential candidate Joe Biden has described the incident as "unacceptable" and vowed that, if elected, he would "stand up to autocrats like Putin".
After Navalny was flown to Germany, UK Foreign Secretary Dominic Raab tweeted: "It is vital that there is a full & transparent investigation into his poisoning."
- BBC / Reuters