Q&A: South China Sea dispute
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.Who claims what?
China claims by far the largest portion of territory - an area defined by the "nine-dash line" which stretches hundreds of miles south and east from its most southerly province of Hainan. Beijing says its right to the area comes from 2,000 years of history where the Paracel and Spratly island chains were regarded as integral parts of the Chinese nation.
In 1947 China issued a map detailing its claims. It showed the two island groups falling entirely within its territory. Those claims are mirrored by Taiwan, as the Republic of China.
Vietnam hotly disputes China's historical account, saying China had never claimed sovereignty over the islands before the 1940s. Vietnam says it has actively ruled over both the Paracels and the Spratlys since the 17th Century - and has the documents to prove it.
The other major claimant in the area is the Philippines, which invokes its geographical proximity to the Spratly Islands as the main basis of its claim for part of the grouping.
Both the Philippines and China lay claim to the Scarborough Shoal (known as Huangyan Island in China) - a little more than 100 miles (160km) from the Philippines and 500 miles from China.
Malaysia and Brunei also lay claim to territory in the South China Sea that they say falls within their economic exclusion zones, as defined by UNCLOS. Brunei does not claim any of the disputed islands, but Malaysia claims a small number of islands in the Spratlys.Why are so many countries involved?
The Paracels and the Spratlys may have reserves of natural resources around them. There has been little detailed exploration of the area, so estimates are largely extrapolated from the mineral wealth of neighbouring areas.
The sea is also a major shipping route and home to fishing grounds that supply the livelihoods of people across the region.How much trouble does the dispute cause?
The most serious trouble in recent decades has flared between Vietnam and China. The Chinese seized the Paracels from Vietnam in 1974, killing more than 70 Vietnamese troops. In 1988 the two sides clashed in the Spratlys, when Vietnam again came off worse, losing about 60 sailors.
The Philippines has also been involved in a number of minor skirmishes with Chinese, Vietnamese and Malaysian forces.
The most recent upsurge in tension has coincided with more muscular posturing from China.
The Philippines has accused China of building up its military presence in the Spratlys. In early 2012, the two countries engaged in a lengthy maritime stand-off, accusing each other of intrusions in the Scarborough Shoal.
In July 2012 China formally created Sansha city, an administrative body with its headquarters in the Paracels which it says oversees Chinese territory in the South China Sea - including the Paracels and the Spratlys. Both Vietnam and the Philippines protested against this move.
Unverified claims that the Chinese navy deliberately sabotaged two Vietnamese exploration operations in late 2012 led to large anti-China protests on the streets of Hanoi and Ho Chi Minh City.
Vietnam was also one of a number of nations that refused to stamp new editions of Chinese passports which include a map showing disputed areas of the South China Sea as Chinese territory.
In January 2013, Manila said it was taking China to a UN tribunal under the auspices of the UN Convention on the Laws of the Sea, to challenge its claims in the South China Sea.
In May 2014, the introduction by China of a drilling rig into waters near the Paracel Islands led to multiple collisions between Vietnamese and China ships.Is anyone trying to resolve the row?
Over the years, China has tended to favour bilateral arrangements negotiated behind closed doors - but other countries want international mediation.
Even if the Philippines is successful in its attempts to pursue China at a UN tribunal, however, China would not be obliged to abide by the ruling.
Recent attempts by regional grouping Asean to discuss new ideas for resolving the dispute appear to have left the bloc severely divided.