Russian doctors say leading opposition figure Alexei Navalny remains too ill to be transferred to Germany for treatment after a possible poisoning.
Mr Navalny has been in a coma since Thursday when he fell ill on a flight and his supporters called the doctors' decision "a direct threat to his life".
They have cited a report of "a deadly substance", dangerous not only to Mr Navalny but to all around him.
However, a doctor now says "no poisons have been detected" by the tests.
Mr Navalny is a prominent critic of Russian President Vladimir Putin.
His team suspects a poisonous substance was put in his tea at an airport cafe.
Activists in Germany have sent a plane to bring Mr Navalny to Berlin for treatment.
The head doctor at the hospital in Siberia where he is being treated said Mr Navalny's condition had improved a little, but that he was still unstable. Alexander Murakhovsky said legal questions would need to be resolved before Mr Navalny could be moved.
But Mr Navalny's team said it was "deadly" for him to remain in the hospital.
"The ban on the transportation of Navalny is an attempt on his life, which is being made right now by doctors and the deceitful authorities who sanctioned it," Mr Navalny's spokeswoman Kira Yarmysh wrote on Twitter.
https://www.bbc.co.uk/news/world-europe-53857563