MANILA, Philippines (AP) — The Philippine government on Monday identified four new local military camps, including some across a sea border from Taiwan, where rotational batches of American forces with their weapons would be allowed to stay indefinitely despite strong objections from China.

President Ferdinand Marcos Jr.’s administration announced in February his approval of an expanded United States (US) military presence in the country by allowing American forces to station in the four additional Philippine military bases under the 2014 Enhanced Defense Cooperation Agreement between the longtime treaty allies.

The move would boost his country’s coastal defence, Marcos said. It dovetails with the Biden administration’s effort to strengthen an arc of military alliances in the Indo-Pacific to better counter China, including in any future confrontation over Taiwan.

The new sites identified by Marcos’ office include a Philippine navy base in Santa Ana town and an international airport in Lal-lo town, both in northern Cagayan province. Those two locations have infuriated Chinese officials because they would provide US forces with a staging ground close to southern China and Taiwan, the self-ruled island Beijing claims as its own.

The two other military areas are in northern Isabela province and a local navy camp on Balabac island in the western province of Palawan.

Palawan faces the South China Sea, a key passage for global trade that Beijing claims virtually in its entirety and where it has taken increasingly aggressive actions that have threatened smaller claimant states, including the Philippines.

China and the Philippines, along with Vietnam, Malaysia, Brunei and Taiwan, have been locked in increasingly tense territorial disputes over the busy and resource-rich South China Sea. Washington lays no claims to the strategic waters but has deployed warships and fighter and surveillance aircraft for patrols that it says promote freedom of navigation and the rule of law, angering Beijing.

“That’s a trade route, that’s where more or less $3 trillion worth of trade passes. Our responsibility in collectively securing that is huge,” Carlito Galvez, who heads the Philippine Defense Department, said.

The four new military sites where Americans would gain access were “suitable and mutually beneficial” and would “boost the disaster response of the country” as springboards for humanitarian and relief work during emergencies, Marcos’s office said.

In a closed doors meeting in Manila with their Philippine counterparts last month, however, a Chinese Foreign Ministry delegation expressed its strong opposition to an expanded U.S. military presence in the Philippines and warned of its repercussions to regional peace and stability, Philippine officials said.

The Chinese Embassy separately warned in a recent statement that the Philippine government’s security cooperation with Washington “will drag the Philippines into the abyss of geopolitical strife and damage its economic development at the end of the day.”

The long-seething territorial conflicts have persisted as a major irritant in Philippine-China relations early in Marcos’ six-year term. His administration has filed at least 77 of more than 200 diplomatic protests against China’s increasingly assertive actions in the disputed waters since Marcos took office last year.

The Philippines used to host two of the largest US Navy and Air Force bases outside the American mainland. The bases were shut down in the early 1990s after the Philippine Senate rejected an extension, but American forces later returned for large-scale combat exercises with Filipino troops under a Visiting Forces Agreement.

The Philippine Constitution prohibits the permanent basing of foreign troops and their involvement in local combat. The 2014 agreement allows visiting American forces to stay indefinitely in rotating batches in barracks and other buildings they construct within designated Philippine camps with their defence equipment, except nuclear weapons.

The Department of National Defense in Manila said the American military presence was not a re-establishment of US military bases in the Philippines, as opponents have asserted.