China said Thursday it would resolutely oppose any military provocation in its territorial waters, remarks which appeared to be directed at the United States, Vietnam and the Philippines.

China's military has established routine naval patrols in the South China Sea, "indisputable territory" of the nation and a matter of "national sovereignty," defence ministry spokesman Geng Yansheng said.

"We will resolutely oppose any military provocations," Geng said in statements posted on his ministry's website.

"The determination and will of China's military to safeguard national sovereignty and territorial integrity is unwavering."

Geng's remarks came as the United States launched the largest-ever "Rim of the Pacific" naval exercises in Hawaii, involving 22 nations, including the US, India, Russia, Australia and the Philippines.

China was not invited to participate or observe the exercises.

Tensions in the South China Sea have intensified recently with Vietnam and the Philippines both accusing China of increasingly flexing its military muscle in the region, despite a pledge from all claimants to avoid actions that could further stoke tensions.

Both the Philippines and Vietnam have also sought to shore up relations with the United States to counter China's increasingly vocal assertions over the region that also includes key international shipping routes.

Geng downplayed the US-sponsored multi-national military exercises, but voiced concerns over Washington's recent announcement to deploy more of its naval forces to the Pacific Ocean.

"Frankly speaking, we do not believe that this (the multilateral exercises) is such a big matter and it is not worth being upset about," Geng, who was speaking at a press briefing that was only open to Chinese journalists, said.

But "deploying more military forces in the Asia-Pacific goes against the world's pursuit of peace, development and cooperation, as well as trust among nations in the region," he said.

The Philippines said Thursday it was committed to "defuse the tension" with China over a disputed shoal, despite the continued presence of Chinese ships in the area.

"While we continue to assert our sovereignty over (the shoal) and sovereign rights over the waters surrounding it, we are committed to defusing the tension in the area through diplomatic discussions and consultations," Department of Foreign Affairs Raul Hernandez said in a statement.

"We urge everyone to refrain from making statements that would tend to re-escalate the situation in the area," the statement added.

China says it has sovereign rights to the whole South China Sea, believed to sit atop vast oil and gas deposits. The sea is also claimed in whole or part by Taiwan, Vietnam, Brunei, Malaysia, and the Philippines.