Kidnappers in the southern Philippines have released a Filipino-American woman who has seized in July, but continue to hold her 14-year-old son and a nephew.

Philippine officials say Gerfa Yeatts Lunsmann was set free late Sunday on Basilan island, a stronghold of militant Islamic groups including the notorious Abu Sayyaf group, which has links to al-Qaida.

Lunsmann, who was raised and lives in the United States, was visiting her home island of Zamboanga when she was kidnapped with her son and nephew on July 12. The kidnappers, who have not identified themselves, reportedly demanded a huge ransom, but it is not clear whether one was paid.

The U.S. embassy in Manila thanked Philippine authorities for their help in securing Lunsmann's release.