A U.S. destroyer used a “maneuvering drill” near Chinese-built islands in the South China Sea to send a message about territorial claims on the water around them, Reuters reported Thursday.

U.S. officials told Reuters that the USS Dewey “engaged in normal operations” by conducting a “man overboard” exercise within 12 nautical miles of Mischief Reef, which houses the Spratly Islands, an area that China and its neighbors have fought over.

Officials said the move was to show that its pass-by was not “innocent passage,” which is when a warship recognizes a territorial sea by crossing it quickly and without stopping.

ADVERTISEMENT

“The ship’s actions demonstrated that Mischief Reef is not entitled to its own territorial sea regardless of whether an artificial island has been built on top of it,” one official said.

The recent patrol drew anger from China, which has been building artificial islands to bolster its claims to the disputed waters.

In response, two Chinese guided-missile warships warned the Dewey to leave the waters. The country also lodged “stern representations” with the United States, according to Beijing officials.

This is not the first time the United States has seemed to challenge Chinese claims on the South China Sea.

In October 2015 the Navy sent a destroyer within 12 nautical miles of an artificial island built by China in the Spratly archipelago. The move infuriated Chinese officials, who called it “dangerous” and “provocative.”

Sen. John McCain John Sidney McCainThe electoral reality that the media ignores Kelly's lead widens to 10 points in Arizona Senate race: poll COVID response shows a way forward on private gun sale checks MORE (R-Ariz.) at the time was critical of the service for not providing more details on patrol, but then-Defense Secretary Ash Carter defended the move.

The patrol was “conducted in full accordance with international law" and was "a normal and routine operation," Carter told lawmakers in January 2016.

And in October 2016 the Navy guided-missile destroyer USS Decatur challenged “excessive maritime claims” near the Paracel Islands by sailing within the waters claimed by China.

White House officials have said the United States will conduct more robust South China Sea operations after former President Barack Obama Barack Hussein ObamaThe Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon Trump appointees stymie recommendations to boost minority voting: report Obama's first presidential memoir, 'A Promised Land,' set for November release MORE was criticized for potentially reinforcing China's territorial claims. The freedom-of-navigation operation Thursday was the first such move since October.

China commonly refers to its maritime claims as the "nine-dash line," which stretches from Taiwan in the north, east to the Philippines, south to Malaysia and west to Vietnam, effectively covering the entire South China Sea.