A Russian doctor said on Friday that the hospital in Siberia treating Kremlin critic Alexei Navalny for suspected poisoning had decided to allow German doctors to fly him to Germany for treatment.

The doctor said the hospital could help transport Navalny to the airport and that he would be moved within several hours.

Navalny, 44, Russia’s most prominent opposition leader, has been in a coma since Thursday in a hospital in the Siberian city of Omsk after he fell ill on a flight. His supporters believe he was poisoned shortly before boarding the plane.