During her trip to Vietnam and Singapore, Vice President Kamala Harris will focus on protecting international rules in the South China Sea, enhancing US leadership in the area, and extending security cooperation, according to a senior White House official.

The trip will be Harris’s first to the region, and she will be the first female vice president of the United States to visit Vietnam. It is intended to garner worldwide support in response to China’s expanding global influence.

Because of their location, size of economies, commercial ties with the US, and security alliance on matters such as the South China Sea, the countries are key partners for the US, according to the official.

Vietnam, a former US rival, has emerged as a vital US ally and vocal opponent of China’s territorial claims in the South China Sea. In the face of Beijing’s fortification of the waterway and its enormous coastguard and fishing fleet, several countries in the region largely favor a US presence.

“We do not want to see any country dominate that region or take advantage of the power situation to compromise the sovereignty of others,” the White House official said.

“The Vice President is going to underscore that there should be free passage for trade, throughout the South China Sea, and no single country should disrespect the right of others,” the official added.

The U.S. Navy has maintained a steady pattern of freedom of navigation operations in the South China Sea and near Taiwan but these appear to have done little to discourage Beijing.

Harris’ trip will follow one that Defense Secretary Lloyd Austin made last week to Hanoi, where he sought to nudge forward security ties that have been steadily deepening amid shared concern about China’s activities in the South China Sea.

It will also follow high-level talks in the northern Chinese city of Tianjin between U.S. Deputy Secretary of State Wendy Sherman and senior Chinese diplomats, which ended with both sides signaling that the other must make concessions for ties to improve.

This will not be Harris’s first meeting with leaders in Asia. She has previously held in-person and virtual bilateral meetings from the White House with the South Korean President Moon Jae-In and the Prime Minister of Japan Suga Yoshihide.

The pandemic, vaccinations and quality of vaccines will also be a top priority for the Vice President, the official said.

Last month, the United States shipped 3 million doses of the Moderna COVID-19 vaccine to Vietnam, bringing total donations to the Southeast Asian country to 5 million.

Harris will meet government, private sector and civil society leaders in both countries. She departs the United States on August 20, arriving in Singapore on Aug. 22. She will visit Vietnam on Aug. 24 and depart on Aug. 26.