Responding to what it says are provocative plans for stepped-up US-Philippine military cooperation, China says it will "resolutely defend" its interests and accuses the two longstanding allies of militarizing the region and harboring a "Cold War mentality."
The ministry's comments came shortly after Thursday's announcement that the US would send troops and planes to the Philippines for more frequent rotations and will increase joint sea and air patrols with Philippine forces in the South China Sea.
In a move likely to further anger Beijing, US Defense Secretary Ash Carter says he will be visiting an aircraft carrier — a potent symbol of US military might — in the South China Sea during his current visit to the region, which does not include a stop in China.
"The joint patrols between the United States and the Philippines in the South China Sea are militarizing the region and are non-beneficial to regional peace and stability," said a statement posted to the ministry's website late on Thursday.
"The Chinese military will pay close attention to the situation, and resolutely defend China's territorial sovereignty and maritime interests," the statement said.
China claims virtually the entire South China Sea as its territory and is building manmade islands there topped with airstrips and other infrastructure. The Philippines, Vietnam and others also claim territory controlled or claimed by China and increased military and coast guard deployments by all sides could increase the potential for conflict.
The ministry's statement also referenced China's long-standing opposition to US military alliances in the region. It regards those as a form of unwelcome interference that stymies its desired status as the pre-eminent military power in the Asia-Pacific.
"Strengthening the US-Philippine military alliance ... is a sign of a Cold War mentality that is unbeneficial to peace and stability in the South China Sea," the statement said.
The South China Sea dispute also featured in talks between Chinese Premier Li Keqiang and Malcolm Turnbull, the prime minister of close US ally Australia which is trying to balance security needs with its economy's reliance on the Chinese market.
"We've always had good and constructive discussions but our position is that all claimants, all claimants, should settle disputes peacefully and in accordance with international law," Turnbull told reporters in Beijing on Friday, a day after his meeting with Li.
Beijing and Washington have repeatedly traded accusations over who is responsible for raising tensions in the South China Sea, with the US citing China's island-building project and efforts to block other disputants from parts of the crucial waterway, through which passes more than $5 trillion in global trade passes each year.
China says its island developments are mainly for civilian purposes and says US naval activities — especially the sailing of ships close to its newly built islands — threatens China's security.