Mohammadi has been moved from prison in Zanjan in northwestern Iran to a hospital after fainting twice and after previously suffering a heart attack, the foundation that bears her name said on Friday.
She should be allowed to come to Tehran immediately to receive specialized care from her own medical team, the Norwegian Nobel Committee wrote in an "urgent message" to Iranian authorities on Saturday:
"Without such treatment, she will remain in mortal danger."
Mohammadi, 54, was arrested in December at a funeral, having already spent much of the past ten years in prison.
She was awarded the Nobel Peace Prize in 2023 for her fight for human rights.
