The Association of Southeast Asian Nations' (ASEAN's) strategy of nurturing diverse economic alliances was on full display as Chinese Premier Li Qiang was warmly welcomed along with Gulf state dignitaries for a lavish gala dinner ahead of talks on Tuesday.

Trump cast international markets into turmoil in April when he announced wide-ranging tariffs, before agreeing to pause them for most countries for 90 days.

In summit opening remarks given to media but not delivered in his speech, Malaysian Prime Minister Anwar Ibrahim said: "A transition in the geopolitical order is underway and the global trading system is under further strain, with the recent imposition of US unilateral tariffs."

"Protectionism is resurging as we bear witness to multilateralism breaking apart at the seams," he added.

Bilateral talks between the ASEAN member states and Washington are in progress, but the bloc is still presenting a united front, according to Malaysia, which holds the rotating ASEAN chairmanship this year.

According to a draft statement seen by AFP, ASEAN will express "deep concern... over the imposition of unilateral tariff measures", saying they "pose complex and multidimensional challenges" to the bloc.

But it said earlier this year it would not impose retaliatory duties.

Instead, it is looking at broadening its scope with other trading blocs, including the European Union, as well as beefing up trade between member states, Malaysia's trade minister said Sunday.

- 'Not just a photo-op' -

Tuesday's talks with Li and the Gulf Cooperation Council -- a bloc made up of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates -- underscores this effort to maintain a broad network of trading partners.

"It's not just a photo-op. It actually demonstrates how ASEAN is attempting to engage strategically with various blocs, a strategy we might term multi-alignment diplomacy," said Khoo Ying Hooi from Malaya University.

Anwar said Monday he had written to Trump to request an ASEAN-US summit this year -- showing "we observe seriously the spirit of centrality".

His foreign minister Mohamad Hasan said Washington had not yet responded.

Despite smiles all round at Monday night's dinner -- and Premier Li donning a matching traditional batik shirt to the ASEAN leaders -- the bloc's relationship with China is a complicated one.

"Please be assured that whatever is being said, or circumstances and complexity, we are here as a friend of China," Anwar said at the dinner.

But on Monday, Philippines leader Ferdinand Marcos told his regional counterparts there was an "urgent need" to adopt a legally binding code of conduct in the South China Sea.

Beijing has territorial disputes in the area with five ASEAN member states, with China and the Philippines having engaged in months of confrontations in the contested waters.

The adoption of the code should be accelerated "to safeguard maritime rights, promote stability, and prevent miscalculations at sea", Marcos said.

- Myanmar conflict -

ASEAN also has internal matters to deal with, including an attempt to increase pressure on member state Myanmar's military junta, whose leaders are barred from summits over a lack of progress on a five-point peace deal agreed on by the bloc in 2021.

"One thing for sure that we agreed is that Myanmar's government... must comply with the five points consensus which they themselves agreed on as one of the signatories," Mohamad said Sunday.

ASEAN has led so far fruitless diplomatic efforts to end the conflict, triggered when the junta staged a coup deposing civilian leader Aung San Suu Kyi in February 2021.

Mohamad called Sunday for an extension and expansion of a ceasefire declared after a deadly earthquake, despite ongoing fighting bringing its effectiveness into question.

Also on ASEAN's agenda was the prospect of adding an 11th member state before the end of the year.

East Timor, Asia's youngest nation, "has made meaningful progress" for it to "hopefully" join the bloc by the next summit in October, Mohamad said.

After meeting leaders on Monday, East Timor's prime minister said he believed his country would become a full member this year.

"Because everyone supports. Everybody. It was incredible," Xanana Gusmao told reporters.