Following the cancelation of a similar exercise in April, a U.S. Navy missile destroyer has completed a voyage within 12 nautical miles of Fiery Cross Reef, a contested territory in the South China Sea. Beijing responded by demanding the ship leave the area “a dozen times,” CNN reports.

The USS William P. Lawrence passed by the Spratly Island reef — now nearly complete as an artificial island thanks to China’s illegal construction in the region — on Tuesday, triggering military action by China in the region and a stern rebuke from the Foreign Ministry in Beijing. In a statement, the Pentagon called the trip an exercise in “the right of innocent passage,” meant to “challenge attempts by China, Taiwan, and Vietnam to restrict navigation rights around the features they claim… contrary to international law.”

“This operation demonstrates, as President Obama has stated, that the United States will fly, sail, and operate wherever international law allows. That is true in the South China Sea as in other places around the globe,” the Pentagon added.

While the statement mentioned other countries, only China has been attempting to keep other nations out of the area and invested millions into constructing military facilities in the area. China inaugurated an expanded military airbase on the artificial island last year and landed its first military aircraft at Fiery Cross Reef in April, triggering international condemnation.

In response to the USS William P. Lawrence’s presence, in addition to demanding through communications with the ship that it leave, the Chinese government scrambled two fighter jets and sent three military ships to follow the Lawrence out of the area, according to Reuters.

Both Chinese and American officials confirmed that the U.S. Navy did not notify any regional governments of the ship’s presence before it arrived. The United States maintains that it does not need to, as international law allows for free innocent passage through international waters. China does not view the Spratly Island region as international waters, despite claims from Taiwan, Vietnam, and the Philippines that the territory is theirs.

“These excessive maritime claims are inconsistent with international law as reflected in the Law of the Sea Convention in that they purport to restrict the navigation rights that the United States and all states are entitled to exercise,” U.S. Defense Department spokesman Bill Urban told Reuters of the exercise.

“If the world’s most powerful navy cannot sail where international law permits, then what happens to the ships of navy of smaller countries?,” argued Daniel Russel, assistant secretary of state for East Asia and the Pacific, at a press event Tuesday.

The Chinese Foreign Ministry described the peaceful passage through the region as an action that “again proves that China’s construction of defensive facilities on the relevant reefs in the Nansha Islands is completely reasonable and totally necessary.” At his daily press conference, Foreign Ministry spokesman Lu Kang said the presence of the ship in the region “threatened China’s sovereignty and security interests, endangered safety of personnel and facilities on the reef, and jeopardized regional peace and stability.” He once again insisted that China has “indisputable sovereignty” over the Spratly Islands, a claim few nations support.

In late April, a Pentagon official told the Wall Street Journal that, while the United States was planning on conducting such military operations in the region “regularly,” it had canceled a freedom of navigation exercise in April to attempt to “lower the temperature” of diplomatic ties between the U.S. and China. At the time, it was unclear when the United States would choose to conduct such an operation once again.

This is the third such freedom of navigation exercise for the U.S. Navy in the South China Sea. In October 2015, the USS Lassen sailed within 12 nautical miles of the Spratly Islands. In January, the USS Curtis Wilbur also conducted a similar voyage. Both were met with severe condemnation from Beijing.

In November, following the USS Lassen voyage, a U.S. defense official told The Guardian that China should expect such trips in the region “about twice a quarter or a little more than that.”