Egyptian and international civil society groups on Thursday called for the release of the country's most prominent activist, Alaa Abd el-Fattah, after his lawyer indicated that he would remain in detention until 2027.

Egyptian-British software developer and blogger Abd el-Fattah had hoped to be freed on Sunday, when he will have been imprisoned for five years since his latest detention in 2019.

In 2021 he was sentenced to five years in prison on charges of spreading false news after sharing a social media post, but Abd el-Fattah's lawyer said this month that authorities were not planning to include his period of pretrial detention as counting towards his release.

A coalition of 59 Egyptian and international civil society groups said in a joint statement that failing to release Abd el-Fattah on Sept. 29 would violate Egypt's code of criminal procedure.

Authorities have not commented on the release date and did not respond to a request for comment.

Abd el-Fattah's mother Laila Soueif told Reuters she was planning to visit her son on Sunday in a monthly visit, and that on the previous visit "he was acting like he will be released".

"He has been telling me for a month to stop bringing books in order to empty the prison cell," she said in an interview in Cairo.

"As per our tradition, we act as if the right things will happen, and when they don't happen, we protest."

Abd el-Fattah rose to prominence during the 2011 Arab Spring uprising in which former Egyptian leader Hosni Mubarak was overthrown.

He has been imprisoned almost continuously since 2014, becoming a symbol of tens of thousands of people who rights groups say have been jailed in a crackdown that has targeted dissidents from across the political spectrum.

Egyptian President Abdel Fattah al-Sisi, who has overseen the crackdown, says security and stability are paramount and that the state is taking steps to guarantee the rights of its citizens.

In 2022, shortly after obtaining British citizenship, Abd el-Fattah drew global attention by staging a hunger strike that coincided with Egypt's hosting of the COP27 climate summit.

His family said he was close to death when he broke the strike.