MANILA — Vice President Harris will visit the Philippine island chain of Palawan on Tuesday at the end of a week-long trip in Asia, an excursion to the edge of the disputed South China Sea that could raise tensions with Beijing.

Harris, the highest-ranking U.S. official to visit the Philippine archipelago, known as a scenic tropical getaway, will meet with local fishing workers to discuss the impact of the climate crisis and illegal fishing on coastal communities, according to a senior administration official who spoke on the condition of anonymity under ground rules set by the White House. She will then tour a Philippine Coast Guard cutter and deliver remarks about the importance of the freedom of navigation and unimpeded commerce.

China has staked a claim on a majority of the South China Sea, and the Philippines has lodged diplomatic protests against China’s maritime activities in the region, as local fishing communities have reported dwindling fish availability and displacement from their traditional fishing grounds amid hostilities from the Chinese coast guard.

In 2016, Manila scored a victory when an international tribunal ruled that China has no legal basis for its claims, but Beijing has disregarded the ruling.

Harris, signaling U.S. support for the Philippines in the dispute, is undertaking the delicate diplomatic mission at a time when tensions are rising over trade, Taiwan, human rights and other matters. President Biden met recently with Chinese President Xi Jinping, but the two superpowers continue to eye each other warily.

“We stand with you in defense of international rules and norms as it relates to the South China Sea,” Harris said Monday, addressing Philippine President Ferdinand Marcos Jr. in front of reporters. “An armed attack on the Philippines Armed Forces, public vessels or aircraft in the South China Sea would invoke U.S. mutual defense commitments. And that is an unwavering commitment that we have to the Philippines.”

Marcos, the son of former Philippine dictator Ferdinand Marcos, appeared to welcome the support.

“With the upheavals that we are seeing — not only in the region, but especially in the region — these partnerships become even more important,” he said. “The situation is rapidly changing. We must evolve to be properly responsive to that situation.”

Harris is also seeking to raise her political and diplomatic profile after two years as vice president. As Biden has signaled he will announce a reelection bid early next year but has not made a final decision, Harris is seeking to build a base as his heir apparent in the face of potential Democratic rivals.

The visit concludes a week-long trip in Thailand and the Philippines for Harris, who met with other world leaders, including Xi, at a two-day Asia-Pacific Economic Cooperation summit in Bangkok that focused on supply-chain and security issues. On the sidelines of APEC, Harris spoke to business leaders about the U.S. role in the economic development of the region.

She also convened an emergency meeting of the leaders of Japan, South Korea, Australia, New Zealand and Canada after North Korea fired an intercontinental ballistic missile that landed near Japan, condemning the launch as a “brazen violation of multiple U.N. Security resolutions.”

In her conversation with Xi, Harris said she emphasized the importance of keeping “open lines of communication available,” adding that it echoed the three-hour-long discussion President Biden had with his Chinese counterpart on the sidelines of the Group of 20 summit in Bali, Indonesia.

“We welcome competition, but we do not seek conflict,” she told reporters.

Complicating matters, Brunei, Malaysia, Taiwan and Vietnam also claim parts of the disputed area.

Harris’s outreach to the Philippines is part of a broader connection the Biden administration is seeking to forge with Asian countries to counter China’s influence. Her visit to Palawan, the White House official said, reflects an effort to emphasize the need for all countries to follow international law.

Marcos joked to Harris that she was visiting Palawan for a leisure trip. “I’m sure you’re just going to the resorts and the beaches,” he said. Harris responded with a laugh, saying, “That is not the life I’ve chosen these days.”

Harris announced Monday that the Biden administration is eyeing additional locations under the Enhanced Defense Cooperation Agreement that allows the United States access to Philippine military bases, such as Palawan’s Antonio Bautista Air Base. The White House also said it would negotiate a civilian nuclear pact between the United States and the Philippines.

Asked whether Beijing might see Harris’s trip to Palawan as a provocation, Marcos downplayed that possibility.

“It’s very clearly on the Philippine territory,” he told reporters at APEC, according to local reports. “I don’t think it will cause problems.”