Plans to deepen U.S.-Philippine military ties, including joint patrols in the South China Sea, reflect a "Cold War mentality", China's defense ministry said, pledging to resolutely oppose any infringement on the country's sovereignty.
The comments, published on the defense ministry's website late on Thursday, 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 U.S.-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 defense ministry said.
China claims most of the energy-rich waters of the South China Sea, through which about $5 trillion in ship-borne trade passes every year. But the Philippines, Brunei, Malaysia, Taiwan and Vietnam also have claims.
U.S. and Filipino soldiers take part in the annual "Balikatan" (shoulder-to-shoulder) war games with Filipino soldiers at a military camp, Fort Magsaysay, Nueva Ecija in northern Philippines April 20, 2015.
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 U.S.-Philippine naval patrols "promote the militarization of the region", the Chinese defense 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, U.S. Defense Secretary Ash Carter said on Thursday the broader American military presence was not meant to provoke conflict with the Chinese.