The Philippines has granted the United States expanded access to its military bases, the countries said on Thursday, amid mounting concern over China’s increasing assertiveness in the disputed South China Sea and tensions over self-ruled Taiwan.

Statements from the defence ministries of both countries said Washington would be given access to four more locations under an Enhanced Defense Cooperation Agreement (EDCA) dating back to 2014.

The United States had allocated more than $82 million toward infrastructure investments at the existing five sites under the EDCA, the statements said.

EDCA allows US access to Philippine military bases for joint training, pre-positioning of equipment, and the building of facilities such as runways, fuel storage, and military housing, but not a permanent presence.

US Defense Secretary Lloyd Austin was in Manila for talks as Washington seeks to extend its security options in the Philippines as part of efforts to deter any move by China against self-ruled Taiwan.

The statements did not specify where the new locations would be. The former Philippine military chief said previously the United States had requested access to bases on the northern land mass of Luzon, the closest part of the Philippines to Taiwan, and on the island of Palawan, facing the disputed Spratly Islands in the South China Sea.

Austin also met with Philippine President Ferdinand Marcos Jr at the presidential palace on Thursday before meeting with his counterpart Carlito Galvez.

His visit follows a three-day trip by US Vice President Kamala Harris to the Philippines in November which included a stop in Palawan.