Philippine President Benigno Aquino Saturday urged fellow Southeast Asian leaders to face up to the threat posed by China's contentious claims to most of the South China Sea as they headed to a regional summit.

Manila filed a case at a UN tribunal in March challenging Chinese claims to most of the strategic sea. Aquino said he would discuss the case's regional implications with fellow Association of Southeast Asian Nations (ASEAN) leaders meeting in Myanmar.

Even though not all ASEAN members are involved in maritime territorial disputes with China, Aquino said the issue concerned the security of the region as a whole.

"We wish to emphasise, uphold and follow the rule of law in resolving these territorial issues so that the rights of all countries involved will be recognised and respected," Aquino said in a speech at Manila airport.

"This step mirrors our belief that an issue that affects all countries in the region cannot be effectively resolved merely through a dialogue between two countries," he added.

Aquino said the issue concerned the "security" of Southeast Asia.

Myanmar is hosting the two-day meeting amid a flare-up of high-seas tensions between ASEAN members Vietnam and the Philippines and regional superpower China, also one of their main economic partners.

China claims most of the South China Sea, including waters and rocks close to the shores of its neighbours, and the Philippines and Vietnam have both accused Beijing of increasingly aggressive moves to assert its claims.

These claims also overlap those of Taiwan, as well as ASEAN members Brunei and Malaysia.

The sea is crisscrossed by fishing and shipping lanes and is thought to contain huge oil and gas reserves.

Hanoi said this week that Chinese ships that had surrounded a Chinese deep-water oil rig in waters claimed by Vietnam had used water cannon against, as well as rammed, Vietnamese patrol vessels there.

Meanwhile, Manila said it arrested 11 crew members of a Chinese-flagged fishing boat Tuesday for poaching hundreds of protected marine turtles in waters that are part of the Philippines' exclusive economic zone.

China has rejected arbitration in the Philippines' UN case, preferring to settle the issue through bilateral negotiations while insisting its sovereignty over these areas was "indisputable".

The other ASEAN members are Cambodia, Indonesia, Laos, Myanmar, Singapore and Thailand.

The weekend summit in Naypyidaw follows a visit to Asia late last month by US President Barack Obama in which he restated support for Asian allies the Philippines and Japan, which is locked in its own maritime territorial dispute with China.

More than 5,000 US and Filipino troops are currently engaged in annual war games in the Philippines, with a focus on maritime security.

China says rig operating within its territory in South China Sea
Beijing (UPI) May 9, 2013 - Chinese drilling operations near the Xisha Islands in the South China Sea are normal and within Beijing's territorial waters, the Chinese Foreign Ministry said.

Yi Xianliang, deputy director-general of ocean affairs at the Chinese Foreign Ministry, challenged claims from Vietnam that a drilling rig was operating in Vietnamese waters.

PetroVietnam, the country's state-owned energy company, said last weekend drilling rig HD-981, deployed by the China National Offshore Oil Corp. about 120 miles off the coast of Vietnam, was encroaching on its sovereignty. The Vietnamese government said it would take "all the proper and necessary measures" to protect its interests.

Yi said Thursday said the Chinese government, however, was "deeply surprised" by Vietnam's reaction. The rig, he said, was operating completely within Chinese territorial waters.

U.S. State Department spokeswoman Jen Psaki said during her regular press briefing Thursday the Chinese side was taking "provocative" actions over the dispute. It's not for the United States to determine territorial claims, though "dangerous conduct [by China] ... is concerning," she said.

China and Vietnam have made competing claims of aggression in the ongoing row.

China is at odds with many of its territorial neighbors over claims to the South China Sea.

"We believe that all sides should operate in a way that reduces tensions," the State Department spokeswoman said.