The pastor taken hostage in Zamboanga last week is among seven released by Moro National Liberation Front (MNLF) rebels, although others remain captive.
Fourteen more have escaped, and nine have been rescued. After eight days of fighting, the Philippines Air Force is firing rockets on MNLF fighters who have been holding parts of the city.
The MNLF seeks to ultimately establish an Islamic state in Mindanao. Latest figures from the province suggest 62 have been killed and 112 wounded so far; about 100 rebels have been killed or captured. As many as 70,000 are thought to have fled their homes for 28 evacuation centres, including an overcrowded grandstand.