TAIPEI (Taiwan News) — Two American warships transited the Taiwan Strait on Sunday (Aug. 28), the first such transit since U.S. House Speaker Nancy Pelosi’s visit to Taiwan at the beginning of the month which infuriated China.

The U.S. 7th Fleet reported that two Ticonderoga-class guided-missile cruisers, the USS Antietam (CG 54) and USS Chancellorsville (CG 62), conducted a routine Taiwan Strait transit “through waters where high seas freedoms of navigation and overflight apply in accordance with international law.”

The U.S. Navy also said that the Antietam and the Chancellorsville sailed through “a corridor in the Strait that is beyond the territorial sea of any coastal State.” The transits also demonstrate the American “commitment to a free and open Indo-Pacific.”

“The United States military flies, sails, and operates anywhere international law allows,” the U.S. Navy added. Meanwhile, John Kirby, a spokesperson for the National Security Council, told CNN that the Sunday transit sent a “very clear” and “very consistent” message that “the United States military will sail, fly, and operate wherever international law permits us to do so.”

In response, China’s Eastern Theater Command said it was monitoring the U.S. ships and warning them, according to Reuters. “Troops in the theater remain on high alert and are ready to thwart any provocation at any time,” it said in a statement.

Military tensions in the region have been heightened ever since Pelosi’s Taiwan visit on Aug. 2 and 3, which Beijing responded to by launching missiles over Taiwan and carrying out military exercises.