Days after Biden's face-to-face meeting with Xi Jinping, Kamala Harris is making a rare trip to a South China Sea hotspot

• Vice President Kamala Harris is traveling to Thailand and the Philippines this week.
• Harris will stop in Palawan, becoming the highest-ranking US official to visit the Philippine island.

Vice President Kamala Harris departed for Southeast Asia on Wednesday, traveling again to an important corner of Asia as President Joe Biden wraps up a separate visit to the region that included his first in-person meeting as president with Chinese leader Xi Jinping.

Harris' trip to Thailand and the Philippines will have its own milestone: a visit to the southern Philippine island of Palawan.

"This is another historic visit, as the vice president is the highest-ranking US official ever to visit Palawan," a senior administration official told reporters on Tuesday.

Palawan is on the eastern edge of the South China Sea and offers a valuable perch from which to monitor activity in the sea, where China has built military outposts and made aggressive claims that have worried its neighbors and the US.

After the APEC economic leaders' summit and other meetings in Bangkok, Harris will travel to the Philippines and meet with her counterpart and with President Ferdinand Marcos Jr. on Monday.

With Marcos, Harris will focus on "strengthening our security alliances and our economic relationship," the official said, speaking on background to describe the trip's agenda.

In the discussion on security, Harris intends to "reaffirm our defense commitments to the Philippines and the importance of our alliance and peace and stability in the South China Sea," the official said, adding that the leaders "will discuss upholding international rules and norms."

In Palawan on November 22, Harris plans to "meet with residents, civil society leaders, and representatives of the Philippine Coast Guard" to demonstrate the US's "commitment to stand with our Philippine ally in upholding the rules-based international maritime order in the South China Sea," the official said.

Palawan, the Philippines' largest province, comprises nearly 2,000 islands stretching from the central Philippines to Malaysia's northeastern tip on the island of Borneo. It divides the Sulu Sea and the South China Sea, where the Philippines is one of several countries that dispute Beijing's expansive claims.

"Geographically, Palawan is important because it's located closest to some of the key Chinese artificial island outposts in the Spratlys," said Collin Koh, a research fellow at the S. Rajaratnam School of International Studies in Singapore.

Southern Palawan also allows for "overwatch" of the straits between those seas, "which could also be used by the Chinese military for movements around the area," Koh told Insider.

Staging air and naval operations out of Palawan saves time and fuel compared to operating from bases in the northern Philippines, added Koh, an expert on maritime security in the South China Sea.

Washington and Manila agreed a decade ago to expand the US presence and support other projects at some Philippine military bases — including an air base in Palawan — under the Enhanced Defense Cooperation Agreement. That work was delayed under Marcos' predecessor, who was more antagonistic toward the US and made overtures to China.

This week, however, Manila said work on agreed-upon projects was "slated for implementation" in 2023. The Philippine military's chief of staff also said this week that US had expressed interest in more projects, including one in Palawan.

Harris' trip reflects the emphasis the US has put on maritime security — particularly on combatting illegal, unregulated, and unreported fishing, for which it says China is the worst offender — in the Pacific as it steps up engagement there, part of a broader effort to counter China's growing influence.

During the US-ASEAN summit in May, Harris announced $60 million for new US Coast Guard-led maritime initiatives in the region, including the deployment of a new cutter for local training.

While in Palawan, Harris "will see firsthand the outcomes of this partnership and discuss how to strengthen it even further with new funding and initiatives," the official said, adding that the trip would "highlight the perils and risks to locals from illegal and unreported fishing."

The Spratlys are a focal point for the dispute between the Philippines and China. To mark its claim, Manila grounded a navy ship on a shoal there in 1999. The ship is still an active outpost with a small troop contingent. China has demanded Manila remove the ship and has tried to block resupply missions dispatched from Palawan.

In Japan in September, Harris said China was using its military and economic heft to "coerce and intimidate its neighbors," and her visit to Palawan now, shortly after Biden and Xi's meeting, may wrankle Beijing, which has sharply criticized US challenges to its activity in the South China Sea.

Asked on Tuesday how China should view the trip, the US official said, "China can take the message it wants. The message to the region is the United States is a member of the Indo-Pacific. We're engaged. We're committed to the security of our allies."