Rival countries have wrangled over territory in the South China Sea for centuries - but a recent upsurge in tension has sparked concern that the area is becoming a flashpoint with global consequences.
What is the argument about?
It is a dispute over territory and sovereignty over ocean areas and the Paracels and the Spratlys - two island chains claimed in whole or in part by a number of countries. Alongside the fully fledged islands, there are dozens of uninhabited rocky outcrops, atolls, sandbanks and reefs, such as the Scarborough Shoal.