The brother of Iranian Nobel Peace Prize winner Narges Mohammadi says he fears her life is in imminent danger after she suffered a suspected heart attack in prison in north-western Iran.

Hamidreza Mohammadi, who is based in Norway, told the BBC that the 53-year-old human rights activist was found unconscious in her bed by fellow inmates at Zanjan Prison last week.

She was taken to the prison infirmary but officials refused to transfer her to a hospital despite her history of heart and lung problems, he said. She also suffers from severe blood pressure fluctuations.

He demanded that she be released immediately for a thorough medical examination.

He also warned that strikes and explosions near the prison since the start of the US-Israeli war with Iran a month ago had only added to her stress.