U.S. Vice President Kamala Harris sharply criticized China over its incursions in the disputed South China Sea, accusing Beijing of "coercion" and "intimidation."

Harris also affirmed that the U.S. will support its allies in the region against Beijing’s advances.

"We know that Beijing continues to coerce, to intimidate and to make claims to the vast majority of the South China Sea," she said in a major foreign policy speech Tuesday in Singapore in which she laid out the Biden administration’s vision for the Indo-Pacific. "Beijing’s actions continue to undermine the rules-based order and threaten the sovereignty of nations."

The speech sought to cement the U.S. commitment to supporting its allies in an area of growing importance to the Biden administration, which has made countering China’s influence globally a centerpiece of its foreign policy.

Harris, who is on a weeklong swing through Southeast Asia, declared that the U.S. "stands with our allies and our partners" in the face of threats from China.

"These unlawful claims have been rejected by the 2016 arbitral tribunal decision, and Beijing's actions continue to undermine the rules-based order and threaten the sovereignty of nations," she said, referring to an international tribunal's ruling over China's claims in The Hague.

China rejected the ruling and has stood by its claim to most of the waters within a so-called Nine Dash Line on its maps, parts of which Brunei, Malaysia, the Philippines and Vietnam also claim.

China has established military outposts on artificial islands in the waters, which are crossed by vital shipping lanes and that also contain gas fields and rich fishing grounds.

The address Tuesday morning at Singapore’s iconic Gardens by the Bay waterfront park offered an opportunity for the former state attorney general and U.S. senator to prove her fluidity with diplomatic and security issues.

Harris' remarks also come during a critical moment for the United States as the Biden administration seeks to further solidify its pivot towards Asia while America’s decadeslong focus on the Middle East comes to a messy end with the chaotic withdrawal from Afghanistan.

Harris' remarks echoed and expanded upon remarks she delivered at the U.S. Naval Academy graduation in June, where she described a world that is "interconnected," "interdependent" and "fragile."

The U.S. Navy regularly conducts "freedom of navigation" operations through the disputed waters, maneuvers that China objects to, saying they do not help promote peace or stability.

On Monday, Harris told sailors aboard a U.S. combat ship at the Changi naval base in Singapore that "a big part of the history of the 21st century will be written about this very region" and that their work defending the region was pivotal.

"It is in our vital interest to stand united with our allies and our partners in Southeast Asia in defense of a free and open Indo-Pacific," she said.

Harris also met Monday with Singapore President Halimah Yacob and Prime Minister Lee Hsien Loong. The vice president’s office announced a number of agreements out of that meeting aimed at combating cyberthreats, tackling climate change, addressing the COVID-19 pandemic and alleviating supply chain issues.

"Our partnerships in Singapore, in Southeast Asia and throughout the Indo-Pacific are a top priority for the United States," Harris said, adding the region was "critically important to our nation's security and prosperity."

After her speech Tuesday, Harris will hold a roundtable discussion with business leaders on supply chain issues, and then travel to Vietnam, where she’ll meet with top officials Wednesday.

President Joe Biden himself has repeatedly emphasized his focus on China as one of America’s main adversaries, pledging in a February speech at the State Department to "confront China’s economic abuses; counter its aggressive, coercive action; to push back on China’s attack on human rights, intellectual property, and global governance" – a message he echoed again later that month to European allies at the virtual G-7 Summit and Munich Security Conference.

And in recent months, his administration has ramped up outreach to the Indo-Pacific region, with Defense Secretary Lloyd Austin and Deputy Secretary of State Wendy Austin both visiting the area in the spring and summer. Secretary of State Antony Blinken also held a number of virtual meetings with Southeast Asian officials earlier this month.

Harris said the U.S. had put itself forward to host a 2023 meeting of the 21-member Asia-Pacific trade group APEC, which includes the U.S., China and Russia.

The chaotic U.S. withdrawal from Afghanistan, however, complicated that message of support to the region, raising questions about the U.S. commitment to its allies. While Biden said last week that an indefinite engagement would’ve benefited "true strategic competitors" China and Russia, China has seized on the images of violence from the evacuation to slam the U.S. for its engagement there.

Harris opened her speech Tuesday talking about Afghanistan and said the U.S. was "laser focused" on the task of "safely evacuating American citizens, international partners, Afghans who worked side by side with us, and other Afghans at risk."

Chinese Foreign Ministry spokesperson Wang Wenbin said Monday that the U.S. had done "unscrupulous and dishonest things" in Afghanistan and called on the nation to help rebuild.

"The United States is the root cause and the biggest external factor in the Afghan issue," Wenbin said. "It cannot just run away like this."

But Harris, during a joint news conference with Prime Minister Lee on Monday, said that her presence in the country, combined with the agreements around greater cooperation that the Biden administration has pursued with Indo-Pacific countries, speak "volumes in terms of the integrity of the relationships that the United States has around the world on many issues."