Store cashier Ledejie Tomarong and two children had been snatched by at least six gunmen who failed to kidnap the teen's employer, a wealthy bakery owner, in Zamboanga del Sur province.
They were apparently seized to use as human shields. Sulu provincial military commander Col Alan Arrojado said the 18-year-old Tomarong dashed to freedom as the militants fled the troops and villagers found her.
Officials said the gunmen killed one of the children, who kept crying. Abu Sayyaf is considered a terrorist organisation for deadly bombings, kidnappings for ransom and extortion in the south.