Nearly 7,000 American and Filipino troops began annual military exercises Monday that will include combat drills near disputed South China Sea waters.
U.S. and Philippine officials stressed that China, which in the past has protested military exercises involving American forces near the contested region, was not an imaginary target in the drills.
They said the Balikatan _ Tagalog for shoulder-to-shoulder _ exercises would mostly focus on humanitarian missions and disaster preparedness but would also include combat maneuvers including the mock retaking of an oil rig supposedly seized by terrorists near the South China Sea.
Asked if China should be alarmed, U.S. Marine Lt. Col. Curtis Hill said in a news conference that the exercises would not focus on any nation as an adversary.
"There is no reason for anyone to feel threatened by us coming together, working through our inter-operabilities so we can better respond and help people across the region," Hill said.
But the larger than usual American attendance at the high-profile event reflects U.S. efforts to reassert its presence in the Asia-Pacific region as a counterweight to China's rise, a move that has rattled Beijing.
In the past, the exercises were held in Philippine regions grappling with decadeslong Muslim and communist insurgencies and threats from al-Qaida-linked militants. This year's main venue, the southwestern island province of Palawan, lies near South China Sea areas disputed by China, the Philippines and four other countries.
Philippine military chief Gen. Jessie Dellosa said at an austere opening ceremony that the Balikatan exercises were timely "given the international situation we are in." He did not elaborate.
"It is imperative for our ground forces to sustain operational readiness, keeping in mind the critical times that we are in now," Dellosa said. "It is during these times that our alliances must be reaffirmed."
The underfunded Philippine military has sought ships, fighter jets and radars from Washington and other allies after Filipino officials accused China last year of repeatedly intruding into its territorial waters in and near contested areas like the Spratly Islands. A U.S.-supplied warship began to patrol the disputed waters last year.
China has dismissed the Philippine claims, saying it has sovereignty on those areas since ancient times.
The Spratlys disputes have long been feared as Asia's next potential flashpoint for armed conflict.
Aside from the Spratlys, China and the Philippines have contested ownership of offshore areas near northwestern Palawan where the Philippine government has invited foreign investors to explore for oil and gas. It's near those waters where U.S. marines would train Filipino counterparts in defending an oil rig from security threats in the current exercises, Philippine military officials said.
Last week, a tense naval standoff erupted between Chinese and Philippine ships at the Scarborough Shoal, about 500 kilometers (310 miles) north of the Spratlys.
Chinese and Philippine diplomats failed to end the dangerous impasse after resuming talks on Monday.
"No breakthrough," Chinese Embassy political officer Bai Tian told reporters after the talks at Manila's Department of Foreign Affairs.
Associated Press writer Teresa Cerojano contributed to this report.