Once opposed to the prospect of a major naval base inside the Philippines' picturesque Ulugan Bay, fearing it would mean bars and brothels for visiting sailors, local residents now look forward to the arrival of American and other foreign warships.

The reason is China, whose rapid creation of artificial islands in the disputed Spratly chain of the South China Sea is setting off alarm bells across the Philippines, a country with one of the weakest navies in the region.

Nowhere is that concern more palpable than around Ulugan Bay, a large sheltered expanse of pristine blue water along the western Philippine coastline that lies 160 km from the Spratlys.