US Navy ship joins patrols in southern Philippines

MANILA — U.S. and Philippine navy ships have patrolled waters in the southern Philippines where kidnappings by ransom-seeking Abu Sayyaf militants have sparked a regional security alarm.

President Rodrigo Duterte, who has moved to bolster economic and security relations with China, has threatened to bar U.S. counterterrorism forces in the south, saying they could be targets of attacks and were fueling Muslim restiveness in the volatile region.

The U.S. military deployed a P3 Orion aircraft recently to southern Marawi city upon Philippine request to help provide surveillance to Filipino troops battling militants aligned with the Islamic State group who laid siege on the mostly Islamic city starting last month.