Gunmen released late Thursday one of three South Korean hostages in the restive southern Philippines, a radio station reported Friday.Regional police commander Chief Supt. Jufel Adriatico of the northern Mindanao region told a radio station that Choi Inn was abandoned by his captors around 9:35 p.m. Thursday on the borders of Madamba town of Lanao del Sur province and Salvador town of Lanao del Norte province after they were pressured by the military and police pursuit operation.\"He (Choi) was rescued after abandoned by the kidnappers,\" Adriatico was quoted as saying, adding Choi was immediately brought to a hospital for examination and treatment.Choi, along with companion Woo Shu Bong and Kim Nam Dou failed to return to their hotel in the southern Philippine city of Cagayan de Oro after a trip to inspect a mining area on Oct. 21.