Mohammed Mahdi Akef, a former supreme guide of Egypt's Muslim Brotherhood, died in a Cairo hospital on Friday at the age of 89.
In a brief statement to Anadolu Agency, Akef's daughter Alia confirmed her father's death, saying burial services would be held later this evening.
In a Facebook post made earlier Friday, Alia said, "My father is in the care of Allah. We all come from Allah and we will all return to Allah."
Akef had been taken to central Cairo's Al-Qasr al-Aini hospital following a rapid deterioration of his health, Brotherhood lawyer Abdel-Moneim Abdel-Maqsoud said in a press statement.
Born in 1928, Akef served as the Brotherhood's seventh supreme guide, assuming the post following the death of his predecessor, Mamoun al-Hudaibi, in 2004.
After Akef resigned from the post in 2010, he was replaced by Mohamed Badie, the group's current leader, who has remained in prison in Egypt since that country's 2013 military coup.
Akef was slapped with a raft of criminal charges following the 2013 coup against Mohamed Morsi, Egypt's first democratically-elected president and a leading Muslim Brotherhood member.
Sentenced to 25 years behind bars in a court ruling that was later overturned, Akef was in the middle of a retrial at the time of his death.
