Two female political prisoners in Iran in a joint letter have announced a three-day hunger strike in protest to being deprived of medical care.

Human rights activist Narges Mohammadi and British-Iranian dual citizen Nazanin Zaghari-Ratcliff have complained that, despite international and Iranian laws and their repeated pleas, their right to receive medical care has been denied.

They write in their letter that a doctor accredit by prison authorities has ordered that they receive medical care “on an emergency basis” but prison authorities have simply ignored the request.

In protest the two prisoners have said they will go on a three-day hunger strike.

Nazanin Zaghari-Ratcliffe was arrested in April 2016 at the international airport in Tehran, when she was leaving the country after a visit with her family. She was charged with ambiguous accusations of spying and plotting against the Islamic Republic and sentenced to five years in prison.

Zaghari-Ratcliffe, who works for the Thomson Reuters Foundation – the media organization’s philanthropic arm – is the mother of a four-year-old daughter and has not been an opposition activist.

Her lawyer had previously confirmed that he had filed a request for medical care, but in the letter Mohammadi and Zaghari-Ratcliff say all their requests have gone unanswered.