May 3 (Reuters) - A foundation run by the family of Nobel Peace Prize laureate Narges Mohammadi said on Sunday that she was in critical condition in a cardiac care unit in northwest Iran, two days after being transferred from prison to the hospital.

Narges Mohammadi’s foundation said in a statement that her blood pressure continued to change dangerously, and that treatment was limited to attempts to stabilize her condition by supplying her with oxygen.

Mohammadi was transferred from prison to a hospital in the northwestern city of Zanjan on Friday following a "catastrophic deterioration" in her health. The organization said Mohammadi suffered a complete loss of consciousness and a severe heart attack.

Mohammadi, who was in her fifties, won the Nobel Peace Prize while imprisoned for campaigning for women's rights and the abolition of the death penalty in Iran. Her family believes she suffered a heart attack in late March.

The foundation said in its statement on Sunday, "Narges Mohammadi's condition cannot be effectively treated unless she is transferred to her medical team in Tehran."

The foundation stated in February that Mohammadi had been sentenced to seven and a half years in prison just weeks before the United States and Israel launched their war on Iran. The Nobel Committee at the time called on Tehran to release her immediately.

She was arrested in December after condemning the death of lawyer Khosrow Ali Kordi. The prosecutor told reporters at the time that she had made provocative remarks at Ali Kordi's memorial service.