US Secretary of State Antony Blinken (L) delivers his speech during the ASEAN Post Ministerial Conference with the United States at the 57th Association of Southeast Asian Nations (ASEAN) Foreign Ministers' Meeting in Vientiane on July 27, 2024. Achmad Ibrahim / POOL / AFP

US Secretary of State Antony Blinken hit out at China's "escalatory and unlawful actions" in the South China Sea on Saturday, hours before he was due to hold talks with Beijing's top diplomat at a regional meeting in Laos.

Blinken is in capital Vientiane for the Association of Southeast Asian Nations (ASEAN) foreign ministers meeting, part of an Asian tour aimed at reinforcing regional ties in the face of an increasingly assertive Beijing.

He has prioritised promoting a "free and open" Asia-Pacific region -- a thinly veiled criticism of China's regional economic, strategic and territorial ambitions.

The United States and ASEAN had to work together to "address challenges," Blinken told ministers from the 10-member bloc, including China's "escalatory and unlawful actions taken against the Philippines in the South China Sea over the last few months."

Manila is locked in a longstanding territorial row with Beijing over parts of the strategic waterway through which trillions of dollars worth of trade passes annually.

On Saturday Manila said it had successfully resupplied troops on the Second Thomas Shoal -- the focus of violent clashes between Chinese and Philippines vessels in recent months.

The mission was carried out under a deal agreed with Beijing last week.

"We are pleased to take note of the successful resupply today," Blinken said.

"We applaud that and hope and expect to see that it continues going forward."

Blinken is due to meet China's Wang Yi later Saturday.

The two will "exchange views on issues of common concern", China's foreign ministry spokeswoman Mao Ning said Friday.

China and Russia

This is Blinken's 18th visit to Asia since taking office more than three years ago, reflecting the fierce competition between Washington and Beijing in the region.

He notably arrives two days after the foreign ministers of China and Russia met with the 10-nation ASEAN bloc -- and each other on the sidelines of the summit.

Wang and Sergei Lavrov had discussed "building a new security architecture for Eurasia", according to Moscow's foreign ministry.

The pair also agreed to jointly "counter any attempts by extra-regional forces to interfere in Southeast Asian affairs", it said.

China has a strong political and economic partnership with Russia, with NATO members labelling Beijing as a "key facilitator" of Moscow's involvement in the war in Ukraine.

Stormy seas

The temperature between Manila and Beijing remains high, despite the deal last week on resupplying Filipino troops stationed on a disputed reef.

"We hope China implements the agreement," Philippine foreign secretary Enrique Manalo told reporters in Vientiane late on Friday.

"I think that would be an important step forward in diffusing tensions and hopefully lead to other areas of cooperation on the South China Sea."

Beijing claims the waterway -- through which trillions of dollars of trade passes annually -- almost in its entirety despite an international court ruling that its assertion has no legal basis.

A Filipino sailor lost a thumb in the latest June 17 confrontation when Chinese coast guard members wielding knives, sticks and an axe foiled a Philippine Navy attempt to resupply its troops.

China lashed out earlier this year after Blinken said that Washington was ready to defend the Philippines if its forces, ships or aircraft came under attack in the South China Sea.

Beijing has insisted that the United States has "no right" to interfere in the South China Sea.

The two countries also remain at loggerheads over trade, human rights and the status of the self-ruled island of Taiwan, which China claims sovereignty over.

Blinken is scheduled to travel to Hanoi later Saturday to extend US condolences to Vietnamese officials after the passing of communist leader Nguyen Phu Trong.

ASEAN ministers are expected to issue a joint communique at the end of their three-day meeting.

One diplomatic source said the statement is being held up by lack of consensus over the wording of paragraphs on the Myanmar conflict and disputes in the South China Sea.

Myanmar's junta has been banned from high-level ASEAN summits over its 2021 coup and crackdown on dissent but has sent two bureaucrats to represent it at the Laos talks.