China has warned countries in Asia to be vigilant about the US "using" them, after American forces secured access to a further four military bases in the Philippines.
The United States already had access to five military bases in the Philippines, and would be given access to four more locations under the 2014 Enhanced Defense Cooperation Agreement (EDCA), US Defense Secretary Lloyd Austin and Philippines Defence Secretary Carlito Galvez said during a joint news conference at the Philippines' military headquarters in Manila.
Mr Austin has led efforts to reinforce regional security partnerships and update the arming and positioning of American and allied forces in Asia in the face of China's increasing military strength and its assertiveness regarding its claims to Taiwan and increasing parts of the South China Sea.
Speaking from the Philippines, Mr Austin referred to the decision as a "big deal" as he and his counterpart reaffirmed their commitment to bolstering their alliance.
"Our alliance makes both of our democracies more secure and helps uphold a free-and-open Indo-Pacific," said Mr Austin, whose visit follows one by US Vice-President Kamala Harris in November, which included a stop at Palawan Island in the South China Sea.
Mr Austin said discussions included actions to address "destabilising activities in the waters surrounding the Philippines", and strengthening "mutual capacities to resist armed attack".
"That's just part of our efforts to modernise our alliance. And these efforts are especially important as the People's Republic of China continues to advance its illegitimate claims in the West Philippine Sea," he added.
China said greater US access to Philippines' military bases undermined regional peace and stability.
"Regional countries should remain vigilant about this and avoid being used by the US," China's foreign ministry spokesperson Mao Ning said in a regular briefing.
Outside the military headquarters, dozens of protesters opposed to a US military presence chanted anti-US slogans and called for the EDCA to be scrapped.
US strengthen ties regionally
The announcement from the Philippines follows Mr Austin's announcement with South Korean leaders on Tuesday that the US would be sending more fighter jets and bombers, and his January 11 declaration with Japanese counterparts that the US would be shifting its deployment there to make for a more nimble fighting force.
There have been other announcements from the Biden administration on arms, exercises and pacts, including a 2021 decision to provide nuclear-powered submarines to Australia.
China's threat to the international order was "unprecedented", US and Japanese diplomats and defence chiefs said after that deal.
"This behaviour is of serious concern to the alliance and the entire international community, and represents the greatest strategic challenge in the Indo-Pacific region and beyond."
Mr Austin thanked President Ferdinand Marcos Jr, whom he briefly met in Manila, for allowing the US military to broaden its presence in the Philippines, Washington's oldest treaty ally in Asia.
The Philippine Constitution prohibits the permanent basing of foreign troops as well as their involvement in local combat.
However, the EDCA allows US access to Philippines' military bases for joint training, pre-positioning of equipment and the building of facilities such as runways, fuel storage and military housing, but not for a permanent presence.
The United States has announced it is allocating more than $US82 million ($115.85 million) for infrastructure at the bases.
Mr Galvez, the Philippines' defence chief, declined to give the location of the four additional camps, saying that announcement would come after talks with surrounding communities.
The country used to host two of the largest US Navy and Air Force bases outside the American mainland.
Those bases were shut down in the early 1990s, after the Philippines Senate rejected an extension, but American forces later returned for large-scale combat exercises with Filipino troops.
Ties between the United States and its former colony were soured under the previous president, Rodrigo Duterte, who made overtures towards China and was known for anti-US rhetoric and threats to downgrade military ties.
Mr Marcos Jnr has met President Joe Biden twice since the son of former dictator — who was also called Ferdinand Marcos — won a landslide victory in an election last year and reiterated he could not see a future for his country without its longtime treaty ally.
"I have always said, it seems to me, the future of the Philippines — and, for that matter, the Asia-Pacific — will always have to involve the United States," Mr Marcos told Mr Austin.
ABC/wires
