The Philippines and Vietnam are whipping up a new spat over the South China Sea. China should take more measures to safeguard its maritime territory.

On Tuesday, Chinese fishermen at a lagoon in China's Huangyan Island were harassed by a Philippine naval gunboat. The Chinese Embassy to the Philippines lodged a complaint with the Philippine Foreign Affairs Department on Wednesday, urging the Philippines to immediately leave the area.

In another development, Vietnamese and Russian companies have reportedly inked deals on gas exploration in the South China Sea. Hanoi is apparently trying to involve a big power like Russia in its territorial disputes with Beijing.

The latest moves by China's two neighbors are beyond tolerance. They are blatant challenges to China's territorial integrity.

Countries like the Philippines and Vietnam have seized considerable economic benefits from the South China Sea in covert or overt ways in recent years. Since the late 1970s when the waters were discovered to have rich deposits of oil and natural gas, they have been competing with one another to seize Chinese isles and reefs in order to illegally tap the resources.

Manila and Hanoi must stop coveting interests that they are not entitled to. They should remember that sailing in troubled waters can be risky.

China attaches great importance to maintaining friendly and good-neighborly ties with countries in the region, including the Philippines and Vietnam, and it has always exercised the utmost restraint as it desires a stable peripheral environment.

But Beijing's restraint should not be misconstrued, it does not lack the means and resources to act more boldly in defense of its territorial integrity.

It seems the troubled waters have become the frontline of escalating tensions in Asia, and there is ample evidence that the United States is using the disputes as a stepping-stone to interfere in Asia.

In a wide-ranging speech on US policy toward the Asia-Pacific region on Tuesday, US Secretary of State Hillary Clinton brushed off talk of a new Cold War in Asia between the US and China. However, it was Clinton that rekindled the South China Sea feuds, when she made a direct link between US national interests and the maritime disputes while attending a major regional forum in Southeast Asia in July 2010.

Washington should adjust its mindset so that it plays a more constructive role in the Asia Pacific.