Back in early April, a Philippine navy frigate tried to arrest Chinese fishermen accused of poaching sharks and giant clams.
But more is at stake than a boatload of seafood.
Neighboring countries say confrontations like this are growing as China asserts claims to territory well beyond its coastline. And analysts think China is testing America's resolve in the region.
Philippine officials say China still has more than 30 boats in the contested area, which is widely known as Scarborough Shoal, though the Chinese call it Huangyan Island.