The amnesty marks end of the holy month of Ramadan. On Monday radical Islamist group Hamas, which controls the Gaza Strip, freed 30 members of the pro-presidential Fatah movement, and pledged to free another three soon.
Hamas began mass arrests of rival Fatah members in July in Gaza, accusing the group of carrying out a bomb attack that killed six people. Fatah denied all accusations and detained several Hamas supporters in response.
Hamas seized Gaza in June 2007, taking control from Palestinian President Mahmoud Abbas' Fatah movement.