The United States will halt Chinese aggression in Southeast Asia and elsewhere in the Indo-Pacific by strengthening the deterrence posture of American military forces, Defense Secretary Pete Hegseth told Asia defense chiefs in Singapore.

“The United States is committed to working with our allies and partners to deter aggression by Communist China in the Indo-Pacific,” Mr. Hegseth said during an opening session of the Shangri-La Dialogue, an annual defense conference.

To counter aggression, the U.S. is reestablishing deterrence “through strength” and standing “shoulder to shoulder” with regional allies, he said.

“We will unite against those who threaten a free and open Indo-Pacific,” Mr. Hegseth said of the alliance.

The defense secretary’s remarks come as China has stepped up aggressive military activities in the South China Sea near the Philippines, around Taiwan and further north near Japan and South Korea, all key regional allies of the U.S.

China is claiming an estimated 90% of the strategic South China Sea despite an international tribunal ruling that the claim is illegitimate.

The waterway sees an estimated $5 trillion annually in international trade, and China has encroached on the sea over the past decade by reclaiming disputed islands and deploying anti-ship and anti-aircraft missiles on some of them.

China, in the past, sent its defense minister to the Singapore meeting. But this year, Beijing did not send a senior general or admiral to the conference, an indication that the Chinese military is less inclined to engage with regional military and defense chiefs.

Mr. Hegseth, in his opening remarks, said U.S. efforts to keep the peace in the face of Chinese aggression are focusing on supporting partners, like those at the meeting.

Earlier, Mr. Hegseth held talks with Philippines Secretary of National Defense Gilberto Teodoro, Singapore Prime Minister Lawrence Wong and Singapore Defense Minister Chan Chun Sing.

The Pentagon said Mr. Hegseth commended Mr. Teodoro for his country’s “standing up against China’s aggressive actions targeting lawful Philippine activities in the South China Sea.”

China’s navy and coast guard have been attempting to force Manila to remove a grounded Philippine warship at Second Thomas Shoal that is being used as a base for marines.

Chinese vessels also have conducted aggressive activities against the Philippines’ resupply ships, including ramming, firing water cannon, and, in a few cases, using lasers against Philippine​ seamen.

“A key part of our success will be empowering allies and partners, like all of you, to even better defend your territory and to ensure peace and security in this region,” Mr. Hegseth said. “That is what we want. That’s our overarching message here. We seek, and we want peace and security and stability.”

Mr. Hegseth said the U.S. military’s mission in the region is to deter war and to be ready for conflict if deterrence fails.

The Pentagon is expanding military cooperation among many of the states that are part of the regional Association of Southeast Asia Nations (ASEAN), many of whom are represented at the conference.

One area where the United States is seeking closer ties to allies is through increased cooperation against cyberattacks and unauthorized network intrusions.

Planning is also underway for a second U.S.-ASEAN maritime exercise later this year.

The exercise will involve training for multilateral information sharing and real-time incident response at sea.

“We believe this is critical because all of you are on the front lines upholding maritime security in the region, and we will continue to maintain, as [U.S. Indo-Pacific Command commander] Admiral [Sam] Paparo does so well — a steady drumbeat of trainings and exercises throughout Southeast Asia,” Mr. Hegseth said.

The training exercises help build military professionalism and increase the interoperability of U.S. and regional militaries.

“On a basis of mutual interest and mutual trust, overlapping interests that intersect, I’m confident that we can deter aggression and achieve peace through strength,” Mr. Hegseth said.

• Bill Gertz can be reached at bgertz@washingtontimes.com.