U.S. Defense Secretary Pete Hegseth stated on Friday the U.S. intends to deepen its military alliance with the Philippines as a deterrent to Chinese aggression in the contested South China Sea.

Hegseth’s assurance was given during a meeting with Philippine President Ferdinand Marcos Jr. in the Philippines. The visit is part of Hegseth’s effort to reaffirm Washington’s “ironclad” commitment to the region under President Donald Trump’s administration.

“Deterrence is essential globally, but particularly in this region, in your country, given the threats from China,” Hegseth told Marcos. “Allies must stand together to prevent conflict and ensure freedom of navigation, whether it’s called the South China Sea or the West Philippine Sea.”

“Peace through strength is a tangible concept,” Hegseth said, commending the Philippines for its steadfast defense of its interests in the disputed waters.

China claims almost all of the South China Sea, a crucial security and global trade route. The Philippines, Vietnam, Malaysia, Brunei, and Taiwan also have competing claims to the resource-rich and busy waters, but confrontations between Chinese and Philippine coast guard and naval forces have increased in the past two years.

Chinese forces have used powerful water cannons and dangerous maneuvers on the high seas to obstruct what Beijing alleges are intrusions by Philippine ships into Chinese waters. Chinese military aircraft have also approached Philippine patrol planes at dangerously close ranges to force them away from the Scarborough Shoal, a highly contested fishing atoll in the disputed waterway.

Hegseth reiterated this commitment by expressing the “ironclad commitment” of Trump and himself “to the Mutual Defense Treaty and to the partnership.”

Marcos told the U.S. defense chief that his visit to the Philippines as his first stop in Asia “sends a very strong message of the commitment of both our countries to continue to work together to maintain peace in the Indo-Pacific region, within the South China Sea.”

“We have always recognized the principle that the greatest force for peace in this part of the world would be the United States,” Marcos said.

Hegseth’s visit to the Philippines precedes the largest annual combat exercises between the longtime allies by one month, which will include live-fire drills.

The defense secretary’s visit occurs while he faces calls for his resignation back home for texting attack plans to a Signal group that included top-level U.S. security officials and the editor-in-chief of The Atlantic magazine.