The Philippines could become embroiled in a conflict because of its 1951 Mutual Defense Treaty with Washington.
The region is troubled by the presence of Abu Sayyaf militants, who are blacklisted by the United States and Philippines.
Capt. Travis Zettel lost his job on board a Navy submarine because of "a loss in confidence in his ability to command."
A C-130 transport plane landed in Manila Tuesday morning carrying three bells taken from the Philippines a century ago.
China has raised concerns about a joint U.S.-Philippine military exercise during Chinese President Xi Jinping's visit.
China is pitted against smaller neighbors in multiple disputes over islands and coral reefs in the South China Sea.
The U.S. Navy, Marine Corps and Coast Guard and Philippine coast guard concluded a five-day search.
Church bells that allegedly signaled an attack on U.S. troops could be returned to the Philippines.
Rodrigo Duterte is angry about the United States. criticisms of his human rights record.
The Balikatan exercises opened with a ceremony at the main Philippine military camp in Manila.