Who claims what?
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
China claims by far the largest portion of territory - an area stretching hundreds of miles south and east from its most
southerly province of Hainan. Beijing has said its right to the area come 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, because the island considers itself the
Republic of China and has the same territorial claims.
Vietnam hotly disputes China's historical account, saying China had never claimed sovereignty over the islands before the 1940s. Vietnam says both island chains are entirely within its territory. It 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.
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.
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 the United Nations Convention on the Law of the Sea in 1982. 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 so keen?
The Paracels and the Spratlys may have vast 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.
Scarborough Shoal. Chinese and Philippine vessels refused to leave the area for a number of weeks, leading to rhetoric and protests.
Chinese officials have given the most optimistic estimates of resource wealth in the area. According to figures quoted by the US Energy Information Administration, one Chinese estimate puts possible oil reserves as high as 213 billion barrels - 10 times the proven reserves of the US. But American scientists have estimated the amount of oil at 28 billion barrels.
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.
According to the EIA, the real wealth of the area may well be natural gas reserves. Estimates say the area holds about 900 trillion cubic ft (25 trillion cubic m) - the same as the proven reserves of Qatar.
The area is also one of the region's main shipping lanes, and is home to a fishing ground that supplies the livelihoods of
thousands of people.
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...