US Secretary of State Antony Blinken condemned Beijing's "increasingly dangerous" actions in the South China Sea as he met leaders of the ASEAN bloc in Laos on Friday.

China has deployed military and coast guard vessels in recent months in a bid to eject the Philippines from a trio of strategically important reefs and islands in the South China Sea.

It has also been ratcheting up pressure over a disputed island group controlled by Japan in the East China Sea, rattling Tokyo and its allies.

"We remain concerned about China's increasingly dangerous and unlawful actions on the South and East China Seas, which have injured people, harmed vessels from ASEAN nations and contradict commitments to peaceful resolution of disputes," Blinken told Southeast Asian leaders gathered in that Laos capital Vientiane.

"The United States will continue to support freedom of navigation and freedom of overflight in the Indo-Pacific," he said. 

The top diplomat said the United States also hoped to work with ASEAN leaders to "protect stability across the Taiwan Strait", a source of constant tension with China.

Beijing this week denounced remarks by Taiwan's President Lai Ching-te who vowed to "resist annexation" by China, which claims the self-governing democracy.

- China disputes -

In an interview with AFP on Friday, EU chief Charles Michel called for disputes to be resolved though peaceful means in the South China Sea.

"International law has to be respected, including the freedom of navigation and including the importance to resolve disputes through peaceful means," he said.

The summit marked the diplomatic debut of Japan's security-minded new Prime Minister Shigeru Ishiba, who in the past has called for a NATO-style Asian pact with an unstated goal of deterring China.

Japan's foreign ministry said Friday that Ishiba reiterated "serious concerns" about the "intensification of Chinese military activities in areas surrounding Japan" in a meeting with Premier Li Qiang.

Li made a veiled swipe at Ishiba during an ASEAN-related meeting on Thursday, warning of the danger of "attempts to introduce bloc confrontation and geopolitical conflicts into Asia".

Philippine President Ferdinand Marcos likewise challenged Li on Thursday over recent clashes in the South China Sea.

- Myanmar crisis -

Leaders at the summit also discussed the situation in Myanmar, whose military junta sent a representative to the ASEAN meeting for the first time in more than three years.

Blinken said he wanted to discuss the "deepening crisis in Myanmar" -- a rare US usage of the country's official name and not the former Burma.

Blinken has urged no let-up in pressure until the junta, which seized power in 2021, moves on key concerns such as freeing political prisoners.

The Myanmar delegation attended the leaders' meeting with Blinken but it was unclear if there was direct interaction between them. 

Thailand separately has led efforts at the summit to seek a diplomatic resolution on violence in Myanmar. 

Blinken also urged firmness against Russia's "war of aggression" in Ukraine, ahead of a full East Asia Summit in which Russian Foreign Minister Sergei Lavrov participated.

The summit marked a rare occasion when the top diplomats of United States and Russia found themselves in the same room. 

Blinken and Lavrov did not appear to make any contact at the start of the talks, with India's Prime Minister Narendra Modi and South Korean President Yoon Suk Yeol sitting between them.

The summit is a change for Blinken from frenetic diplomacy on the Middle East, where Israel has been pounding Hezbollah in Lebanon a year into its Gaza war, triggered by the unprecedented Hamas attack.

The United States has faced criticism over its support for Israel by Russia and China but also by usually US-friendly countries with Muslim majorities -- notably Malaysia and Indonesia.