Hours before Asia’s biggest security summit began, China yesterday accused the Philippines of seeking to negate its sovereignty in the South China Sea after Manila described Taiping Island as a reef and not an island in its territorial court case.

“The Philippines’ attempt to define Taiping Island as a ‘reef’ exposes that the goal of its arbitration case is to try to negate China’s sovereignty and related rights over the Spratly Islands,” said China Foreign Ministry spokeswoman Hua Chunying.

“This is a violation of international law and completely unacceptable,” added Ms Hua, in a statement posted on the ministry’s website.

Tensions in the South China Sea are set to dominate the Shangri-La Dialogue, which started last night and will end tomorrow, exposing a deepening rivalry between the United States and China ahead of a landmark legal ruling over the disputed area in The Hague.

US Defence Secretary Ashton Carter will speak during the dialogue today in a session on meeting Asia’s complex security challenges, while Admiral Sun Jianguo, a deputy chief of the Joint Staff Department of China’s Central Military Commission, will speak on the challenges of conflict resolution tomorrow.

Beijing refuses to recognise the case that Manila lodged with the Permanent Court of Arbitration in The Hague over territorial claims in the South China Sea. China says such disputes should be resolved through bilateral talks.

Manila is challenging the legality of Beijing’s claim there, in part by arguing that no land mass in the Spratly archipelago, including Itu Aba, known as Taiping Island in Chinese, can legally be considered a life-sustaining island.

That would mean China cannot hold rights to a 200 nautical mile exclusive economic zone.

Chinese fishermen had historically lived on Itu Aba all year round, and fished, dug wells, cultivated plants and constructed buildings, all evidence that it was an island capable of sustaining human life and economic activity, argued Ms Hua.

China claims almost the entire South China Sea, through which about US$5 trillion (S$6.8 trillion) worth of ship-borne goods pass every year. Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims to the waters.

Washington has launched a series of patrols near Chinese-controlled islands in the South China Sea, ostensibly to uphold freedom of navigation, drawing Beijing’s ire.

Self-ruled Taiwan controls Itu Aba, which some analysts believe has the strongest claim to island status and an economic zone. Late last year, Taipei finished a US$100 million port upgrade on Itu Aba, which has an airstrip, a hospital and fresh water.

China, which claims sovereignty over Taiwan, has appeared unruffled by Taiwan’s upgrades on Itu Aba. Military strategists say that is because it could fall into China’s hands should it ever take over Taiwan.