Philippine President Ferdinand Marcos Jr. reassured China that military installations that are accessible to the US would not be used in any offensive operations, emphasizing that the US agreement was made to strengthen the Philippine defenses.

When Manila gave Washington access to more of its facilities, China’s foreign ministry warned last week that the United States’ increased military presence in the Philippines will only heighten tensions in the area.

“China’s reaction was not surprising,” Marcos told reporters. “The Philippines will not allow the bases to be used in any offensive action,” he said.

The Philippines identified last week four more of its bases the United States will get access to, almost doubling the number included in its Enhanced Defense Cooperation Agreement (EDCA).

The locations of the bases are significant, with three facing north towards Taiwan and one near the disputed Spratly Islands in the South China Sea, where China has built artificial islands equipped with runways and missile systems.

EDCA underlines the Philippines’ strategic importance to the former colonial ruler the United States, coming at a time of growing concern over China’s conduct in the South China Sea and tension over self-ruled Taiwan.

Signed in 2014, it allows U.S. access to Philippine bases for joint training, pre-positioning of equipment and building of facilities such as runways, fuel storage and military housing, but it is not a permanent presence.

“If no one is attacking us, they need not worry because we will not fight them,” Marcos said. “What we are doing is we are strengthening our territorial defence, the defence of the Republic.”

Marcos’ remarks also come ahead of the largest ever joint military exercises between the Philippines and the United States, which will feature for the first time live fire exercises at sea.