The Deputy Chief Doctor of the hospital in Omsk where opposition politician Alexei Navalny is being treated has given a statement to the press.
Anatoliy Kalinichenko is heard saying to journalists: "Until the patient is discharged from the hospital, there are always some threats."
In response to a question about medical tests, he says: "Even if there is, I cannot tell you.
"I also want to say that his treatment and diagnostics are under the control of our local Ministry of Health.
"If necessary, we can always use the help of federal specialists."
Navalny became unconscious on a flight from Siberia to Moscow forcing the plane to make an emergency landing in Omsk.
A lawyer for Navalny has claimed that there is "no doubt" that he was poisoned.