Salman Rushdie has welcomed the release of the Syrian activist Mazen Darwish from prison after almost three-and-a-half years.

Darwish, founder of the Damascus-based Syrian Centre for Media and Free Expression, had been detained in February 2012 following a raid by Syrian Air Force Intelligence of his offices, according to English PEN. Along with colleagues Hani Al-Zitani and Hussein Gharir, he was imprisoned on charges of “publicising terrorist acts” and reportedly subjected to torture, said PEN.

His case was highlighted by Rushdie last October, when the Booker-winning novelist shared his PEN Pinter prize with the lawyer, journalist and activist. At the time, Rushdie called Darwish’s detention “arbitrary and unjust”, praising how the writer “courageously fought for civilised values – free expression, human rights – in one of the most dangerous places in the world”. PEN believes that Darwish, Al-Zitani and Gharir were being held “solely for the peaceful exercise of their right to freedom of expression”.

On Monday, Rushdie said he was delighted by the good news about Darwish’s release. “Congratulations to Mazen Darwish and his family, and to English PEN for so energetically, and successfully, highlighting and pursuing his case,” the novelist said.

Darwish’s release was confirmed by Yara Bader, his wife and director of the Syrian pressure group. “The Syrian Centre for Media and Freedom of Expression welcomes [our] colleague Darwish, and congratulates him [on] his freedom,” Bader said in a statement on Monday. “After the arbitrary arrest that lasted three years, five months, and 23 days, Mazen Darwish was released today.”

But while Darwish has been released, the charges against him are understood to remain, and according to Bader he is scheduled to attend a court hearing on 31 August, about which English PEN said it remained “seriously concerned”.

“We are so relieved that Mazen Darwish has finally been released, and happy for Mazen and his wife Yara Bader,” said director Jo Glanville. “Yara has been a great inspiration to us all throughout the campaign for his release, and we hope that they will be reunited very soon. However, we also remain concerned for Mazen and his colleagues Hani al-Zitani and Hussein Gharir and will continue to call for charges against them to be dropped immediately and unconditionally.”

Al-Zitani and Gharir were released in July following a presidential pardon, but still face criminal charges. PEN says that Syria is one of the world’s most dangerous countries for journalists; it is ranked 177th out of 180 in the 2015 World Press Freedom Index, which says that in 2014, 15 journalists and 17 net-citizens were killed there.