China strongly condemned the United States after a U.S. warship deliberately sailed near one of the Beijing-controlled islands in the hotly contested South China Sea to exercise freedom of navigation and challenge China’s vast sea claims.

The missile destroyer USS Curtis Wilbur sailed within 12 nautical miles (22 kilometers) of Triton Island in the Paracel chain “to challenge excessive maritime claims of parties that claim the Paracel Islands,” without notifying the three claimants beforehand, Defense Department spokesman Mark Wright said Saturday in Washington.

China, Taiwan and Vietnam have overlapping claims in the Paracels and require prior notice from ships transiting what they consider their territorial waters. The latest operation was particularly aimed at China, which has raised tensions with the U.S. and its Southeast Asian neighbors by embarking on massive construction of man-made islands and airstrips in contested waters.

Vietnamese Foreign Ministry spokesman Le Hai Binh said that Vietnam respects “innocent passage” of ships through territorial waters in line with international law. State media quoted Binh as reiterating Vietnam’s sovereignty over the Paracels and Spratlys and calling on nations to actively and practically contribute to peace and stability in the South China Sea.

The U.S. has claimed the attempts to restrict navigational rights by requiring prior notice are inconsistent with international law and pledged to regularly carry out similar maneuvers.

In October, another U.S. warship sailed in the nearby Spratly Islands near Subi Reef, where China has built one of seven artificial islands.

The latest operation also drew Beijing’s ire. Defense Ministry spokesman Yang Yujun issued a statement saying the “unprofessional and irresponsible” U.S. action “severely violated Chinese law, sabotaged the peace, security and good order of the waters, and undermined the region’s peace and stability.”

In an opinion published Sunday by the official Xinhua news agency, China described the maneuver as a “deliberate provocation” that raised doubts about the United States’ sincerity just days after Secretary of State John Kerry visited Beijing for meetings about the South China Sea and North Korea that were called productive by both sides.

China’s official response has been restrained compared to the public outrage seen online, according to Xinhua. A social media search on Sunday showed a smattering of posts calling on China to adopt a tougher military posture against U.S. encroachment — if not wage war with the United States.

China claims almost the entire South China Sea and its islands, reefs and atolls on historic grounds. The area has some of the world’s busiest shipping lanes, and U.S. officials say ensuring freedom of navigation is in U.S. national interests, while not taking sides in the territorial disputes.

China seized the unpopulated Triton Island, an area of 1.2 square kilometers (0.46 sq. miles), from former South Vietnam in 1974. In May 2014, China parked a huge oil drilling platform off the Vietnamese coast in the area, prompting Vietnam to send fishing boats and coast guard vessels to harass the rig and nearby Chinese vessels. Skirmishes led to collisions and the capsizing of at least one Vietnamese boat.

(AP)