A worker adjusts an ASEAN flag at a meeting hall in Kuala Lumpur, Malaysia, October 28, 2021.
A worker adjusts an ASEAN flag at a meeting hall in Kuala Lumpur, Malaysia, October 28, 2021. Reuters / LIM HUEY TENG

Southeast Asia's regional bloc ASEAN is "deeply disappointed" by the limited progress made by Myanmar's military rulers in implementing a peace agreement to end the conflict in the country, a communique issued by its foreign ministers said.

The communique was issued on Friday and comes as ASEAN chair Cambodia hosts a broader international gathering, including counterparts from the United States, China, Russia, Japan, Britain and Australia.

The gathering has been overshadowed by tensions over developments around Taiwan following U.S. House of Representatives Speaker Nancy Pelosi's solidarity trip to self-ruled the island this week, which has infuriated Beijing.

Chinese Foreign Minister Wang Yi and Russian Foreign Minister Sergei Lavrov walked out of a plenary meeting on Friday when their Japanese counterpart spoke, a person in the room said.

Wang had cancelled a meeting with Japan's Yoshimasa Hayashi in Cambodia on Thursday, with China citing displeasure over a G7 statement urging it to resolve tension over Taiwan peacefully.

The Association of Southeast Asian Nations had warned on Thursday of the risk of miscalculations in the Taiwan Strait and "serious confrontation" among major powers, though Friday's communique did not mention Taiwan.

The communique did, however, bring up Myanmar's crisis since last year's coup and recommended that an ASEAN summit in November assess progress by the junta in implementing the peace plan "to guide the decision on the next steps".

"We extensively discussed the recent developments in Myanmar and expressed our concerns over the prolonged political crisis ... including the execution of four opposition activists," the communique said.

Myanmar is an ASEAN member but its generals, who have defended the recent executions as necessary, are barred from attending its meetings until progress in the ASEAN peace plan is demonstrated.

The five-point peace "consensus" calls for an end to violence and includes all parties to engage in dialogue and for ASEAN to provide humanitarian assistance.

But there has been little sign of the violence in Myanmar ending, with conflict spreading after the army crushed mostly peaceful protests in towns and cities.

Cambodian Prime Minister Hun Sen had said at the start of the meeting that ASEAN would be forced to reconsider the peace plan if Myanmar's military rulers execute more prisoners.

A senior State Department official also said this week the United States was "looking what can be done to both sustain and increase the pressure" on the Myanmar generals.

Some members of ASEAN, which has a tradition of non-interference in each other's internal affairs, have been strident in their criticism of Myanmar.

Malaysian Foreign Minister Saifuddin Abdullah said the junta has been frustrating everyone in ASEAN and making a mockery of the peace agreement, which should be inclusive of its opponents.

ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam

The ASEAN ministers were joined on Friday for plenary sessions of the East Asia Summit and the annual ASEAN Regional Forum security gathering, attended by 27 foreign ministers.

"I have to say that never before, not like this year, have we been confronted with so many perils at the same time," Cambodian Foreign Minister Prak Sokhonn said ahead of a plenary session, citing the COVID-19 pandemic.

Illustrating the tensions over Taiwan, China's Wang arrived for ASEAN's gala dinner late on Thursday, then walked out of the venue just moments after, according to Reuters journalists.

Wang and U.S. Secretary of State Antony Blinken have refused to meet each other in Phnom Penh.

Blinken told the plenary meeting on Friday that China's reaction to Pelosi's visit to Taiwan was "flagrantly provocative", a western official said.