Mikheil Saakashvili said he considers himself "Putin's prisoner", according to Ukraine's Public Defender.
Ukraine's Public Defender Lyudmila Denisova has reported that Georgia's ex-President Mikheil Saakashvili "is getting weaker every day".
Denisova visited Saakashvili in prison on Wednesday.
He has been on hunger strike since his arrest on 1 October and his vital signs are decreasing daily.
Saakashvili and his team have called upon the Georgian government to allow his transfer to a private clinic for treatment but they say he can only be taken to the prison hospital.
Georgia's Public Defender issued a statement on Monday saying that it is not equipped to provide emergency aid.
Denisova told reporters at the gates of the Rustavi penitentiary after visiting the former leader that "he refused a transfer to prison hospital number 18 because he thinks his life would be in danger from prisoners who are serving their terms there."
After eight years in exile Saakashvili returned to Georgia ahead of crucial municipal elections to galvanise his supporters but was arrested after uploading a video on social media showing he was on Georgian territory.
Saakashvili was sentenced in absentia to a total of nine years in prison in 2018 on two separate abuse of power charges: Pardoning former Interior Ministry officials wanted in a high profile murder and organising attacks on an opposition MP.
Saakashvili rejects the sentences as politically motivated.
"My life is under question, I am quoting (Saakashvili), so his life is under question," Denisova said Thursday. "He considers himself Putin's prisoner and said that most of all he does not want to harm Ukraine and lead to bloodshed in Georgia. Therefore, he would do everything to avoid this."