The Philippines will station new fighter jets and two frigates at the former U.S. naval facility in Subic Bay from early next year, officials said, the first time the massive installation has functioned as a military base in 23 years.

Using Subic Bay would allow the Philippine air force and navy to respond more effectively to Chinese moves in the disputed South China Sea, security experts said. Subic Bay’s deep-water harbor lies on the western side of the main Philippine island of Luzon, opposite the South China Sea.

“The value of Subic as a military base was proven by the Americans. Chinese defense planners know that,” said Rommel Banlaoi, a Philippine security expert.

Once one of the biggest U.S. naval facilities in the world, Subic Bay was shut in 1992 after the Philippine Senate terminated a bases agreement with Washington at the end of the Cold War.

Manila converted the facility, which was never home to the Philippine military, into an economic zone.

Defense Undersecretary Pio Lorenzo Batino told Reuters the Philippine military signed an agreement in May with the zone’s operator, the Subic Bay Metropolitan Authority, to use parts of the installation under a renewable 15-year lease.

U.S. warships have called regularly at Subic Bay since 2000, but only to dock during exercises with the Philippine military or to use its commercial facilities for repairs and resupply.

Officials said once Subic Bay becomes a military base again, the U.S. Navy could have much greater access to it under a year-old agreement that gives U.S. troops broad use of local military facilities, although that deal is on ice after it was challenged in the Philippine Supreme Court.sing Subic would be the latest Philippine military move to combat China’s maritime ambitions.

Two FA-50 light attack fighters made by Korea Aerospace Industries, the first among a dozen ordered last year, would be based at the former Cubi Naval Station in Subic Bay from early 2016, two Philippine generals told Reuters. The two planes arrive in December.

The full squadron of FA-50s would be based at Subic, as well as the 5th Fighter Wing, which would relocate from a rundown base in northern Luzon, said the generals, who declined to be identified.

Security experts noted that Subic Bay is only 145 nautical miles (270 km) from Scarborough Shoal, which China seized from Manila in 2012 after a three-month standoff with the Philippine navy.

The disputed Spratly islands, where China is building seven man-made islands, some with military facilities, lie further to the southwest of the shoal.

China, which claims nearly all of the South China Sea, said it was aware of reports of the arms buildup.

“We hope that the Philippines does more to benefit regional peace and stability,” the defense ministry said in a statement faxed to Reuters.