China claims almost all of the South China Sea, but faces competing claims over the Spratlys from Vietnam, the Philippines and Malaysia, as well as Taiwan. The encounter on Sunday occurred within 12 nautical miles of Gaven Reef, a pair of outcroppings in the sea that China has expanded and fortified with weaponry since 2014.

As tensions have increased over trade and other issues, the United States and other nations have intensified naval and aerial patrols in the sea to signal that the territories there remain in international waters. Britain, France and Japan have also conducted operations there in recent months, creating what many in China view as a coordinated campaign.

China’s defense and foreign ministries each released statements on Tuesday sharply criticizing the United States, though not disputing details of the American accusations involving the Decatur.

“The United States has repeatedly sent military ships to South China Sea islands and its adjacent waters, threatened China’s sovereignty and security, seriously damaged the relations between the two countries and militaries, and endangered regional peace and stability,” Senior Col. Wu Qian, a spokesman for China’s Ministry of National Defense, said in a statement.

In 2016, an arbitration panel under the United Nations Convention on the Law of the Sea, ruling in an appeal brought by the Philippines, did not support China’s claims to Gaven Reef, among other shoals and maritime features in the sea. China has ignored the ruling, however, and the fortification of seven artificial islands it has built there has made Chinese control of those waters virtually a fait accompli.