A plane carrying the Russian dissident left for a German hospital on Saturday following much wrangling over Alexei Navalny’s condition and treatment, reports AP.

The plane took off from an airport in the Siberian city of Omsk just after 8 a.m. local time.

Navalny, a 44-year-old politician and corruption investigator who is one of Russian President Vladimir Putin’s fiercest critics, was admitted to an intensive care unit in Omsk on Thursday.

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

Read Also: Russian opposition politician Navalny poisoned, hospitalized

When German specialists first arrived on a plane equipped with advanced medical equipment Friday morning at his family’s behest, Navalny’s physicians in Omsk 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 that it was purely a medical decision.

However, the reversal came as international pressure on Russia’s leadership mounted.

It would not be the first time a prominent, outspoken Russian was targeted in such a way — or the first time the Kremlin was accused of being behind it.

On Thursday, leaders of France and Germany said the two countries were ready to offer Navalny and his family any and all assistance and insisted on an investigation into what happened.

On Friday, European Union spokeswoman Nabila Massrali added that the bloc was urging Russian authorities to allow him to be taken abroad.

Also on Friday, the European Court of Human Rights said it was considering a request from Navalny’s supporters that it urge the Russian government to let the politician be moved.

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.