Southeast Asian and Japanese leaders agreed on Sunday to boost maritime security cooperation in the face of Beijing's growing assertiveness, seen most recently in a spate of confrontations with Philippine vessels.
Beijing claims almost the entire South China Sea, a vital trade corridor, and its increased deployment of vessels and other methods to assert its claims in disputed areas have riled nations across the region as well as Washington.
Without identifying China, Japan and the Association of Southeast Asian Nations (ASEAN) agreed to "strengthen dialogue and cooperation for the maintenance of maritime security and safety (and) maritime order based on the rule of law", a joint statement said after a summit in Tokyo.
Close US ally Japan, which also has territorial and other disputes with China, is hiking defence spending and has expanded security cooperation with countries across the Asia-Pacific region.
Japan announced on Saturday it would deepen ties with Malaysia and provide 400 million yen ($2.8 million) for "warning and surveillance" equipment.
Japan agreed last month to help the Philippines buy coastguard vessels and to supply a radar system, and the two are discussing allowing troop deployments on each other's soil.
Japan expressed "serious concern" last week about "dangerous actions" after the latest tense confrontation between Philippine and Chinese vessels at flashpoint reefs, which included a collision and Chinese ships shooting water cannon.
Philippine President Ferdinand Marcos said in an interview with Japan's public broadcaster NHK on Saturday that "the situation in the (South) China Sea has grown more and more complicated".
"We are at a turning point in history, and the free and open international order based on the rule of law is facing serious challenges while we are facing complex and multiple challenges such as climate change and inequality," Japanese Prime Minister Fumio Kishida said on Sunday.
"While the world is facing complex crises as division and conflict escalate in many places, Japan will tackle the challenges together with ASEAN countries, which are linchpins of the free and open Indo-Pacific," he said, using a term for the Asia-Pacific region used by the US and its allies.
- Automotive hub -
Japan and ASEAN leaders also agreed to strengthen supply chain resilience and to deepen cooperation on tackling climate change, in energy, critical minerals, space and other areas like artificial intelligence and cybersecurity.
In a speech at a dinner he hosted Saturday, Kishida said the leaders will launch an initiative "for the next generation automotive industry", so that ASEAN remains the world's "leading hub for automotive production and export".
Japan was due to host on Monday a meeting of its Asia Zero Emission Community (AZEC) initiative that will see Australian Prime Minister Anthony Albanese joining virtually, officials said.
Tokyo has come under fire from environmental groups for financing fossil fuel projects around Asia and promoting unproven methods aimed at reducing emissions -- like ammonia and carbon capture -- instead of using renewables.
Absent from the ASEAN summit, which marked 50 years of ties with Japan, was Myanmar which has been frozen out of high-level meetings since the military coup of 2021.
Marcos said Sunday that there was a "need to address the worsening violence and the plight of the people of Myanmar through proactive engagement of all the stakeholders involved".