China accused the Philippines on Friday, of seeking to deny its sovereignty in the South China Sea by describing Taiping Island as a reef rather than an island in Manila’s territorial court case; noting that the accusation came by the time Asia’s biggest security summit is set to convene.

Tensions in the South China Sea are to lead the Shangri-La Dialogue (SLD) starting Friday, uncovering an extending conflict between the United States and China ahead of a landmark legal ruling over the disputed area in the Hague.

Beijing declines to recognize the case lodged by the Philippines with the Permanent Court of Arbitration in The Hague over territorial claims in the South China Sea and says such disputes should be resolved through bilateral talks.

Manila is challenging the legality of China’s claim there; 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. The aforementioned mean it cannot hold rights to a 200 nautical mile (370 km) exclusive economic zone.

“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,” China’s Foreign Ministry spokeswoman Hua Chunying said.

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

However, China claims the entire South China Sea, where also Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims to the waters.

China has appeared unruffled by Taiwan’s upgrading work on Itu Aba, and according to Military strategists, that is because it could fall into China’s hands should it ever take over Taiwan.

Taiwan in May called on the international court not to make a ruling on the legal status of Itu Aba in the South China Sea case if the judges don’t visit first to see for themselves it can sustain life.