Baktash Abtin, who had been in a coma battling Covid-19, has died, the Iranian Writers’ Association said on Saturday.
The poet, author and filmmaker had been in hospital in Tehran hospital after contracting Covid-19 at Evin prison, where he was serving a six-year sentence.
He had been charged with “propagating against the regime” and other offences.
Abtin, 48, was placed in an induced coma after his condition worsened.
His supporters have accused the authorities of delaying his transfer from jail to hospital for 10 days.
Abtin was on the board of the Iranian Writers’ Association, which has been banned since the 1980s but has continued to campaign against censorship.
He one of three writers jailed in May 2019 on national security and propaganda charges owing to links with the group.
“The anti-libertarian government took away a freedom-loving hero from us: Baktash Abtin has passed away,” the IWA tweeted on Saturday
Abtin had infected lungs and was transferred from Evin prison to hospital last month, but condition began to deteriorate last week.
Iranian rights groups published a photograph of him in a hospital bed and wearing an oxygen mask.
Abtin, Reza Khandan Mahabadi and Keyvan Bajan served on the board of the IWA and were joint authors of a book about the history of the group, which has been critical of successive Iranian governments for decades.
They were also punished for organising memorial ceremonies for members who had been killed by the state in the 1990s.
Dozens of writers from around the world, including Margaret Atwood, Orhan Pamuk and JM Coetzee, signed a letter to Iranian President Ebrahim Raisi in October calling for the three men’s release.
All three men had been ill since being jailed but had been denied medical treatment, campaigners said.
“The suffering he [Abtin] has suffered this month is a direct result of the actions of the government and the prison guards,” the IWA said on Twitter last week.
A group of Evin political prisoners has blamed the prison and judicial authorities for turning a “treatable and preventable” medical case into a matter of life and death.
The group, whose supporters posted the statement, blamed the authorities for delaying medical leave and not sending sick prisoners to hospital quickly enough.
The Centre for Human Rights in Iran, which is based in the US, said at least 11 writers are either currently in jail in Iran or have been convicted.
All have been punished for “practising and advocating freedom of speech”, it said.