Manila: A female trader held captive by Islamic militants for more than two months was freed on Friday, officials said.

Governor Abdusakar Tan said soldiers discovered a group of Abu Sayyaf rebels holding Maria Rosalie Lao near Patikul town on Jolo island.

"She was found after a brief exchange of gunfire," Tan told reporters, adding her captors decided to leave her behind after she collapsed from fatigue.

"The rebels may have thought she was hit in the crossfire and decided to save themselves rather than worry about a wounded hostage," he said.

Tan said Lao was taken to a military hospital for a medical checkup and was later reunited with her family.