SHANGHAI (REUTERS) - Plans to deepen US-Philippine military ties, including joint patrols in the South China Sea, reflect a "Cold War mentality", China's defence ministry said, pledging to resolutely oppose any infringement on the country's sovereignty.

The comments, published on the defence ministry's website late on Thursday (April 14), come after the United States said it would ramp up its military presence in the Philippines and announced that the two countries had started the joint patrols in the disputed waters.

"A strengthening of the US-Philippine military alliance...is a manifestation of the Cold War mentality and is not conducive to peace and stability in the South China Sea," the defence ministry said.

China claims most of the energy-rich waters of the South China Sea, through which about US$5 trillion (S$6.7 trillion) in ship-borne trade passes every year. But the Philippines, Brunei, Malaysia, Taiwan and Vietnam also have claims.

Countries across the region have express concern over China's growing assertiveness in the region, which has intensified with a rapid buildup of man-made islands in the Spratly archipelago, to which Philippines and Vietnam lay claim.

Joint US-Philippine naval patrols "promote the militarisation of the region", the Chinese defence ministry said, urging that the bilateral military cooperation avoid prejudicing the interests of third parties.

"The Chinese army will monitor this trend closely, and will resolutely safeguard China's territorial sovereignty as well as maritime rights and interests," it said.

Visiting the Philippines, US Defence Secretary Ash Carter said on Thursday that the broader American military presence was not meant to provoke conflict with the Chinese.