According to the prisons office, which is run by Hamas, this includes 50 who had been sentenced to life imprisonment, 60 described as having "high" sentences, 47 prisoners from the "Wafa al Ahrar" 2011 prisoner exchange deal who had since been re-arrested, and 445 who were arrested after 7 October attacks.
Six Israeli hostages have been handed over by Hamas on Saturday, while hundreds of Palestinian prisoners are due to be released.
The "Wafa al-Ahrar" deal was the 2011 prisoner exchange agreement that saw the release of captured Israeli soldier Gilad Shalit in exchange for 1027 Palestinian prisoners.
The Gaza ceasefire deal continues to hold, despite tensions rising this week when Hamas initially handed over the body of an unidentified Palestinian woman instead of Israeli mother-of-two Shiri Bibas.
Israel is expected to free hundreds of Palestinian prisoners later on Saturday, including a man who has been detained for more than 40 years.
