"We need to be 100 percent sure that the safety of Alexei Navalny is guaranteed," PM Morawiecki added.
"I am deeply concerned with reports regarding the poisoning of Alexei Navalny, his health condition and the refusal to let him leave Russia," Morawiecki stated.
Doctors in the Siberian city of Omsk refused to authorise the transfer of the Russian opposition politician to a German hospital, his spokeswoman said Friday.
Navalny remains in a coma in intensive care after a suspected poisoning his allies link to his political activities. The 44-year-old Navalny fell ill on a flight back to Moscow from the Siberian city of Tomsk on Thursday and was taken to a hospital after the plane made an emergency landing in Omsk. His team says a plane with all the necessary equipment is ready to take Navalny to a German clinic. (PAP)