British-Australian academic Kylie Moore-Gilbert has repeatedly attempted suicide while detained in Iran, the Center for Human Rights in Iran (CHRI), a New York-based advocacy group, says.
Moore-Gilbert, a specialist in Middle East politics at the University of Melbourne, has been detained in Iran since September 2018, the statement said.
British and Australian media have reported that she has been sentenced to 10 years in jail by Iranian authorities.
The Iranian judiciary could not immediately be reached for comment.
"Kylie's cries for help are so loud and desperate that even the walls of one of Iran's most notorious prisons can't silence them," CHRI Executive Director Hadi Ghaemi said in a statement.
"The Australian government should heed her pleas and immediately facilitate her access to basic rights that the Iranian government has been denying her for nearly two years, and immediately get her back home where she belongs."
Moore-Gilbert is being held in solitary confinement in a two to three metre cell with a toilet in the Evin prison in Tehran, Reza Khandan, an activist and husband of Nasrin Sotoudeh, an activist lawyer currently imprisoned in Iran, told CHRI.
Moore-Gilbert is forced to wear a blindfold anytime she is taken out of the cell, Khandan told CHRI.
Iran has stepped up detentions of foreign and dual citizens amid a protracted stand-off with the United States after officials in Washington DC withdrew from an international agreement to curb Iranian nuclear activities and reimposed sanctions in 2018.
Australian Associated Press