Allies of stricken Putin critic Alexei Navalny accused the Kremlin of thwarting his medical evacuation to Germany on Friday.
They claimed the decision placed his life in mortal danger because the Siberian hospital treating him was under-equipped
Navalny is in a serious condition after drinking tea on Thursday morning that his allies believe was laced with poison. A doctor on Friday said his condition had improved a little overnight.
Navalny's wife Yulia, and his spokeswoman Kira Yarmysh, spoke out against the Kremlin after the head doctor at the hospital in Siberia treating Navalny said moving him would put his life at risk because he was still in a coma and his condition unstable.
"The ban on transporting Navalny is an attempt on his life being carried out right now by doctors and the deceitful authorities that have authorised it," Yarmysh wrote on social media.
She said doctors had previously consented to his being moved, but had withheld their agreement at the last minute.
"This decision, of course, was not made by them, but by the Kremlin," said Yarmysh.
The Kremlin said on Thursday that medical authorities would promptly consider any request to move him to a European clinic and were being open about his medical condition.
The row broke out as a German air ambulance landed in Omsk, the city where Navalny is being treated, with the intention of flying him to Germany for treatment if possible.
Alexander Murakhovsky, the hospital's head doctor, told reporters that many legal questions would need to be resolved before Navalny could be handed over to European doctors however.
He said top doctors had been flown in from Moscow to treat Navalny. The Moscow doctors were no worse than their European counterparts, he said.
There were five possible diagnoses of Navalny's condition and test results would be available within two days, he said.