(UPDATE) US Secretary of State Antony Blinken on Tuesday assured President Ferdinand Marcos Jr. that the alliance between Washington and Manila was "more than rock-solid" and that it was President Joe Biden's "absolute priority."

Blinken, who arrived in Manila late Monday after a stop in South Korea, reaffirmed this commitment during a courtesy call on Marcos in Malacañang.

BOOSTING TIES US Secretary of State Antony Blinken meets with President Ferdinand Marcos Jr. in Malacañang. PPA POOL

"We are working on a number of challenges around the world and have even discussed them with you, but I think [this is] so important to us... that even with dealing with those other challenges, our focus, our engagement, [and] our commitment to the Indo-Pacific at large and to the relationship [and] alliance between the United States and the Philippines in particular, is more than rock solid," Blinken told Marcos.

"It's the absolute priority of President Biden. That's why he asked me to be here," he added.

Blinken also said that Marcos' upcoming visit to Washington in April would result in a new level of cooperation as the US and the Philippines are set to hold a three-way summit with Japan.

"We have your upcoming visit to Washington to see President Biden and also to have a trilateral meeting with President Prime Minister Kishida; I think a new horizon of cooperation is also incredibly promising," the American official said.

He also stressed that their cooperation is "building on the very strong foundation of our countries" through identical priorities such as economic development, efforts on climate change mitigation, food security, and upholding international law.

"Our relationship between the Philippines and the United States is in hyperdrive if that is a word you're willing to use, and that is so true; we see it across every domain; it's something we attach very great importance to," Blinken added.

Blinken's visit to Manila, his second since Marcos took office in June 2022, is part of his brief Asia tour that also included South Korea.

Marcos thanked Blinken for visiting the country.

"I am happy that...[you had] this chance to come by and visit with us," Marcos told Blinken during the meeting.

In a press conference before he met with the President, Blinken said Washington stands with Manila and reaffirmed America's defense commitments to the Philippines under the Mutual Defense Treaty between the two countries.

Foreign Affairs Secretary Enrique Manalo thanked the US government's "consistent support, especially with regard to recent incidents in the South China Sea."

Blinken's visit to Manila follows a spate of incidents involving Philippine and Chinese vessels in the South China Sea, including collisions, in recent months.

Marcos has expressed "great alarm" over the confrontations that have sparked diplomatic sparring between Manila and Beijing.

Blinken on Tuesday referred to these incidents.

"We have shared concerns with China's actions that threaten our common vision for a free and open Indo-Pacific. Waterways are critical to the interests of the region, the United States and the world," he said.

"These waterways are critical to the Philippines, to its security, [and] to its economy, but they're also critical to the interests of the region, the United States and the world," Blinken said. "That's why we stand with the Philippines and stand by our ironclad defense commitments, including [those] under the Mutual Defense Treaty."

Manalo said Blinken's visit comes at an important juncture in Philippine-US relations. "We've been on hyperdrive over the past year or so," he said.

"Engagements across issue areas and between and among government branches have never been better. The challenge now is how to sustain and further elevate our alliance and partnership," he said.

Manalo said he discussed with Blinken ways to strengthen the defense alliance between the two countries through better coordination at the policy and operational levels.

This is to ensure that it "remains relevant and responsive to current, emerging and cross-cutting challenges in the defense, security and economic spheres, while staying true to our commitment to safeguarding and promoting peace, security, and prosperity in the region, always anchored on the rule of law," he said.

"We discussed regional issues, especially the situation in the South China Sea, and I stated that the Philippines is committed to managing disputes in accordance with our national interests, the rules-based international order and international law, especially Unclos (United Nations Convention on the Law of the Sea)," he said.

Manalo added, "We reaffirmed our shared view that a strong and capable Philippines would make a formidable ally for the United States."

He also underscored the importance of more substantial US investments toward enhancing the Philippines' defense and civilian law enforcement capabilities.

Washington is keen to improve relations with its regional allies, such as Manila and Seoul, in a bid to deter China and North Korea as tensions rise in the South China Sea, over Taiwan and on the Korean peninsula.

Top US officials have repeatedly said that "an armed attack" against Philippine public vessels, aircraft, armed forces and coast guard would invoke the 1951 US-Philippines Mutual Defense Treaty in which Washington is obliged to defend its ally.

Beijing has accused Washington of using the Philippines as a "pawn" in the dispute over the waterway and various reefs.

China claims almost the entire South China Sea, brushing aside competing claims from several Southeast Asian nations, including the Philippines, and an international ruling that has declared its stance baseless.