South China Sea tensions escalate over contested island.

The South China Sea is once again rapidly becoming a major point of contention between Washington and Beijing, with both sides refusing to back down.

Two U.S. Navy warships — the Arleigh Burke-class guided-missile destroyer USS Higgins and Ticonderoga-class guided-missile cruiser USS Antietam — conducted a freedom of navigation operation (FONOP) in the South China Sea Saturday, sailing within twelve nautical miles of several Chinese-controlled islands in the Paracels, territories the Chinese military forcefully seized from Vietnam in the 1970s. In response, Beijing claims it dispatched warships to drive the U.S. ships away.

Asserting that the American vessels entered China's territorial waters "without the permission of the Chinese government," the Chinese Ministry of National Defense explained that the Chinese military "immediately dispatched warships to identify and inspect the American ships according to law, and warned them to depart." This claim has not been verified.

Nonetheless, China clearly intends to pursue a more confrontational approach. "The Chinese army is determined to strengthen the preparations for sea and air combat readiness, raise the level of defense, defend national sovereignty and security," a defense ministry spokesman revealed.

In recent months, China has dramatically bolstered its military presence in the South China Sea.

China dispatched heavy bombers to contested territories in the region in mid-May. "A division of the People's Liberation Army Air Force (PLAAF) recently organized multiple bombers, such as the H-6K, to conduct take-off and landing training on islands and reefs in the South China Sea in order to improve our ability to 'reach all territory, conduct strikes at any time and strike in all directions,'" China's air force said in an official statement.

The statement described the exercises, believed to have been carried out around Woody Island in the Paracels, as preparation for "the West Pacific and the battle for the South China Sea."

China has also deployed YJ-12B anti-ship cruise missiles and HQ-9B surface-to-air missiles to islands in the Spratlys, boosting China's ability to combat U.S. aviation and naval assets should such action be necessary. Such weapons systems also serve as a warning to other claimant states.