"Mum was arrested last (Wednesday) night while she was alone at home," her daughter Mehraveh Khandan wrote on Instagram.

Sotoudeh, who won awards including the 2012 Sakharov Prize of the European Parliament and the 2020 Right Livelihood award, has been repeatedly arrested in the past for her work. Her husband and Mehraveh's father, Reza Khandan, has been held in prison since December 2024.

Mehraveh Khandan said when relatives went to the house they found that "electronic devices, including mum and dad's laptops and phones, had been confiscated".

She added she had had no contact with her mother since her arrest and it was not clear which branch of the security forces had detained her.

Sotoudeh has for years campaigned on some of the most sensitive issues in the Islamic republic, notably working to prevent the execution of youths convicted of crimes committed while minors.

She has also won prominence thanks to appearances in film. She made a memorable cameo as a passenger in Jafar Panahi's 2015 movie "Taxi Tehran", and was the subject of a warmly received 2020 documentary "Nasrin".

Norway-based rights group Iran Human Rights last week warned of the risk of "mass arrests" during the war, saying it had counted the arrests of at least 2,000 people based on official media reports and also recorded 38 arrests of human rights defenders and activists.

Sotoudeh's fellow renowned rights activist Narges Mohammadi, who won the 2023 Nobel peace prize, has been in jail since December when she was arrested after speaking out against Iran's clerical authorities at a funeral.

Mohammadi's health is extremely poor and her life in danger after she suffered a suspected heart attack earlier this month, supporters warned on Tuesday, after she was allowed a rare meeting with her lawyer.