Berlin demands a thorough and transparent investigation into the circumstances of Navalny's illness, German Chancellor Angela Merkel's spokesman, Steffen Seibert, said on Monday.
Seibert did not provide any details about the current health condition of the Russian opposition figure and neither confirmed not refuted earlier media reports saying that Navalny was transported to Berlin as the "chancellor's guest".
According to Seibert, there was a need to ensure Navalny's security, and after talks, it was decided that the Federal Criminal Police Office could help with that.
"There is a suspicion that Navalny was poisoned, and there were several cases of suspected poisoning in Russia in recent years, unfortunately. That is why the world is treating such a suspicion quite seriously", the spokesman added during a press conference in Berlin.
German Foreign Minister Heiko Maas also commented on the issue on Monday. He said that the German government expects clarification from the doctors who have been treating Navalny.
"I am a person who builds his opinions on facts. The Navalny case is still lacking many facts, including medical and, perhaps, criminological," Maas said at a press conference in Kiev following talks with his Ukrainian counterpart, Dmytro Kuleba.
German Medics Set to Make a Statement on Opposition Figure's Condition
Meanwhile, the press service for the Charite clinic in Berlin, where Navalny has been treated, has revealed when a statement about their patient's condition could be made.
"The hospital's spokesman is currently in contact with the medics, the decision on when and how the statement is made will be adopted closer to lunch or early in the evening," the press service said.
Charite has also banned media personnel from its premises due to certain journalists' behaviour, the clinic added. Navalny's wife Yulia visited her husband with journalists trying to follow her around, the German police said.
Navalny was transported to Berlin on Saturday. He fell ill on Thursday while on a flight from the Siberian city of Tomsk to Moscow. The plane had to make an emergency landing in Omsk, where Navalny was hospitalized. His press secretary, Kira Yarmysh, suggested that he may have been poisoned.
Doctors in Omsk said there were no traces of poison in Navalny's blood or urine, citing metabolic imbalance and a sudden drop in blood sugar levels as the main potential diagnoses. The opposition activist is in a coma.
