MANILA -- The USS Ronald Reagan, a hulking American aircraft carrier, made a port call in Manila Bay this week with a message for Beijing: the South China Sea must be free and open.
With a motto of "peace through strength," the Nimitz class vessel with around 70 fighter jets and a crew of about 5,000 is among the largest in the U.S. Navy fleet. Its carrier strike group includes the Ticonderoga class guided-missile cruisers USS Antietam and USS Chancellorsville.
Before anchoring in Manila, the warship sailed through the disputed South China Sea. Tensions are escalating in the vital shipping lane over China's growing assertiveness in areas of the water claimed by the countries including the Philippines and Vietnam, making it a flash point for potential conflict.
"The beauty of this aircraft carrier is that it provides a lot of security and stability in this region," Rear Admiral Karl Thomas, Commander of Task Force 70, told reporters aboard the ship on Wednesday. "It allows us to go out there and set an environment that these disputes can be solved in a peaceful manner and that's our goal, which is to be able to allow our folks to sail and operate wherever international law allows."
But the disputes rage on. Vietnam said on Thursday that a Chinese survey ship had left its exclusive economic zone following a monthlong standoff with Vietnamese vessels. In June, a larger Chinese vessel sank a Philippine fishing boat in the Reed Bank area, which is within the Philippines' EEZ.
China claims most of the South China Sea, including areas that Manila and Hanoi say are part of their respective EEZs. Beijing has built artificial islands in recent years, with some equipped with anti-ship cruise missiles and long-range surface-to-air missiles, according to a Pentagon report in May.
Regular visits by U.S. Navy ships such as the USS Ronald Reagan help keep China's actions in check, according to Gregory Poling, director at the Washington-based Asia Maritime Transparency Initiative, which monitors developments in the South China Sea.
"They also provide opportunities for U.S. Navy assets to operate regularly in the South China Sea, which is helpful in asserting noncompliance with China's efforts to restrict freedom of the seas there," he said.
The aircraft carrier's Manila port call comes as Beijing and Washington are locked in a contest for regional dominance on trade, technology and security fronts. Last week, the U.S. branded China as a "currency manipulator, and speaking in Australia, U.S. Defense Secretary Mark Esper accused China of "destabilizing" the region, saying it is "weaponizing the global commons using predatory economics."
Apart from the port calls, the U.S. and its allies have routinely carried out "Freedom of Navigation Operations" in the South China Sea. Such moves regularly infuriate Beijing.
On the sidelines of the recent ASEAN Regional Forum in Bangkok, Chinese Foreign Minister Wang Yi tacitly pointed a finger at the U.S., saying "nonregional" parties should not meddle in the South China Sea dispute.
Asked about Wang's comments, Commander Thomas said: "The U.S. is a Pacific nation just like any nation in this part of the region, we have a lot of friends, partners and allies... We have a vested interest [and] a national interest that those maritime commons are free and open."
U.S. Navy officials declined to say how long the USS Ronald Reagan would stay in Manila Bay or where it was heading next.
The Philippines is seeking greater reassurance from Washington that the U.S. will come to its defense in the case of an armed attack in the water under a 1951 Mutual Defense Treaty. While President Rodrigo Duterte is pivoting economically toward China, his government has complained about Chinese ships "swarming" Philippine controlled parts of the Spratly Islands.
Aaron Connelly, a research fellow and Southeast Asia expert at the International Institute for Strategic Studies, sees China's aggressive actions in the South China Sea as "an attempt to prompt Duterte and his supporters to continue questioning the merits of the Mutual Defense Treaty."
"The ultimate goal of such a Chinese strategy would be to break the alliance," Connelly said.
But Sung Kim, the U.S. ambassador to the Philippines, said on Wednesday that the aircraft carrier's "visit is a great representation of our strong friendship, partnership, and alliance with the Philippines, as well as a testament to our joint commitment to a free and open Indo-Pacific region."
Amid Washington's reassurances, Duterte's top security advisers have recently issued hawkish comments against China. Defense Secretary Delfin Lorenza last week called China's takeover of Scarbrough Shoal in 2012 "bullying" and National Security Adviser Hermogenes Espeson said the influx of Chinese into the Philippines was a security "threat."
This week, Duterte said he will bring up Manila's 2016 arbitration victory against Beijing over the South China Sea territorial dispute when he visits China later this month. Beijing has rejected the ruling.
Yet, Duterte last month said South China Sea issue required "a delicate balancing act."
Back aboard the aircraft carrier, U.S. Navy officials sought to underscore the long-standing ties between Washington and Manila. They stood in front of large American and Philippine flags and stressed that the ship has more than 250 crew members of Filipino descent.
Flanked by more than a dozen Filipino-American sailors, Thomas said: "This is a magnificent ship with what she can do, but what makes it more magnificent are the sailors that operate this ship and come together as a team... and operate in all the waters around Philippines."