Islamist militants in the Philippines allied with Islamic State freed on Saturday a South Korean cargo ship captain and a Filipino member of his crew held captive for more than three months on a southern island, an army spokesman said.

Park Chulhong, skipper of the South Korea-registered carrier DongBang Giant 2, and Filipino Glenn Alindajao, were brought to the house of the island's governor after they were released by the militants of the Abu Sayyaf group, Major Filemon Tan said.

Members of a Muslim rebel faction cooperating with the government in the south of the predominantly Christian country had helped arrange the release, Tan told reporters.