Russian opposition leader Alexei Navalny still in coma, transferred to Germany after suspected poisoning

 Russian dissident Alexei Navalny, who is in a coma after a suspected poisoning, arrived in Berlin on a special flight Saturday for treatment by specialists at the German capital's main hospital.

"Navalny is in Berlin," Jaka Bizilj, of the German organization that organized the flight, told The Associated Press. "He survived the flight and he's stable."

After touching down shortly before 9 a.m. in an area of the capital's Tegel airport used for government and military flights, Navalny was taken by ambulance to the downtown campus of Berlin's Charite hospital.

The hospital later said extensive tests were being carried out, and doctors would not comment on his illness or treatment until those were completed.

Navalny's spokesperson, Kira Yarmysh, said on Twitter Saturday that the struggle for Alexey's life and health is just beginning, but that with the flight to Berlin, the first step has at least been taken.

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 on Thursday and was taken to the hospital after the plane made an emergency landing. He was admitted to an intensive care unit in the Siberian city of Omsk.

His supporters believe that tea he drank was laced with poison and that the Kremlin is behind both his illness and a delay in transferring him to a top German hospital.

His team made arrangements to transfer him to Charité, a clinic in Berlin that has a history of treating famous foreign leaders and dissidents. But when German specialists arrived in Siberia aboard a plane equipped with advanced medical equipment on Friday morning at his family's behest, Navalny's physicians in Omsk initially said he was too unstable to move.

Navalny's supporters denounced that as a ploy by authorities to stall until any poison in his system would no longer be traceable. The Omsk medical team relented only after a charity that had organized the medevac plane revealed that the German doctors examined the politician and said he was fit to be transported.

Deputy chief doctor of the Omsk hospital Anatoly Kalinichenko then told reporters that Navalny's condition had stabilized and that physicians "didn't mind" transferring the politician, given that his relatives were willing "to take on the risks."

The Kremlin denied resistance to the transfer was political, with spokesman Dmitry Peskov saying it was purely a medical decision. However, the reversal came as international pressure on Russia's leadership mounted.

The most prominent member of Russia's opposition, Navalny campaigned to challenge Putin in the 2018 presidential election but was barred from running. Since then, he has been promoting opposition candidates in regional elections, challenging members of the ruling party, United Russia.

His Foundation for Fighting Corruption has been exposing graft among government officials, including some at the highest level. But he had to shut the foundation last month after a financially devastating lawsuit from a businessman with close ties to the Kremlin.

Like many other opposition politicians in Russia, Navalny has been frequently detained by law enforcement and harassed by pro-Kremlin groups. In 2017, he was attacked by several men who threw antiseptic in his face, damaging an eye.

Last year, Navalny was rushed to a hospital from jail where he was serving a sentence on charges of violating protest regulations. His team also suspected poisoning then. Doctors said he had a severe allergic reaction and sent him back to detention the following day.