The U.S. Navy on Thursday conducted its second “freedom of navigation” (FONOP) operation this year near disputed islands in the South China Sea as the rising Asian nation continues its military buildup in the region.

The Japan-based guided missile destroyer USS Mustin conducted maneuvers within 12 nautical miles (nearly 14 statute miles) of Mischief Reef 150 miles west of Palawan in the Philippines — drawing another rebuke from China.

The Philippines, China, Vietnam and Taiwan all claim Mischief Reef in the Spratly Islands. China has built a runway and hangars that can be used by military aircraft and other facilities on the man-made island.

On Jan. 17, the Pearl Harbor-based destroyer USS Hopper sailed near Scarborough Shoal in the South China Sea. Like Mischief Reef, China claims Scarborough Shoal, about 120 miles west of Luzon in the Philippines, as its territory.

In both instances, China warned the United States not to conduct what it considers to be provocations. The United States does not recognize reclaimed features as Chinese territory.

“U.S. forces operate in the Indo-Pacific region on a daily basis, including the South China Sea. All operations are designed in accordance with international law and demonstrate that the United States will fly, sail and operate wherever international law allows,” Lt. Cmdr. Nicole Schwegman, a spokeswoman for U.S. Pacific Fleet at Pearl Harbor, said in an email.

“We conduct routine and regular freedom of navigation operations, as we have done in the past and will continue to do in the future,” Schwegman said. “FONOPs are not about any one country, nor are they about making political statements. The United States takes a strong position on protecting the rights, freedoms and lawful uses of the sea and airspace guaranteed to all countries and that all maritime claims must comply with international law as reflected in the Law of the Sea Convention.”

Adm. Harry Harris, the commander of U.S. Pacific Command on Oahu, told a congressional committee last month that he was concerned about China’s “aggression” in the South China Sea. China will try to undermine status quo free passage and trade — referred to as the “rules-based international order” — not just in the Asia-Pacific but on a global scale, Harris said.

Harris said China’s island­-building on “reclaimed features” has led to the creation of seven new bases with aircraft hangars, barracks, radars, weapons emplacements and three 10,000-foot runways.

The “increasingly competitive” environment with China necessitates continued dialogue, “but I’ve also been loud and clear that we won’t allow the shared domains to be closed down unilaterally, so we’ll cooperate where we can, but remain ready to confront where we must,” Harris said.