A statement by Philippine president Ferdinand Marcos Jr in response to escalating tensions over Taiwan last month rippled through south-east Asia.

“Bongbong”, as he is known, said US House Speaker Nancy Pelosi’s controversial visit to Taipei “did not raise the intensity” of what was already a fraught political situation and the volatility in the region demonstrated the importance of his country’s ties to Washington.

The president’s comments, made after a meeting with US secretary of state Antony Blinken, were taken by some observers as a pivot away from China and towards the US after the tenure of his predecessor, Rodrigo Duterte.

Analysts have in the past criticised Manila for speaking “from both sides of its mouth” when it comes to the rival powers. But the Philippines’ shift in public rhetoric and the subsequent regional reaction was emblematic of the challenge south-east Asian governments face as they balance the competing pressures of Beijing and Washington.

China, which claims Taiwan as its territory, has stepped up intimidation tactics following Pelosi’s visit. These include the declaration of military exclusion zones that overlap with the exclusive economic zones of Japan and the Philippines, as well as launching ballistic missiles into Tokyo’s EEZ.

Such moves make it “impossible for south-east Asian states to ignore the risks . . . of a cross-Strait conflict”, said Drew Thompson, a visiting senior research fellow at the Lee Kuan Yew School of Public Policy in Singapore.

The dilemma is most obvious in the Philippines, given its proximity to Taiwan. China’s recent maritime live-fire exercises included the part of the Bashi Channel, which sits in Philippines’ EEZ, roughly 40km from its nearest island.

The Philippines has a mutual defence treaty with the US, and Washington would probably seek access to its bases in the event of a conflict, experts said. China would treat the country as a potential launching site for American military action.

“There is no consensus among south-east Asian states about how to mitigate the risks, but the majority agree that they do not want to choose sides or risk antagonising China because of the certainty of disproportional retaliation by Beijing,” Thompson said.

The US has sought to reassure its allies, both to guarantee it would be able to use their bases and avoid them being drawn closer to China. Blinken told Marcos that the US would come to the country’s defence if it was attacked in the South China Sea.

Marcos’s stance marked a substantial shift, according to Hervé Lemahieu, director of research at the Lowy Institute think-tank. Under Duterte, the Philippines was “not in play”, he said, after the former president announced a “separation” from the US and aligned his country more closely with China. “You do have the possibility now that they assist the US,” Lemahieu added.

Richard Heydarian, author of a book about Duterte’s foreign policy, said: “I think the US will push the Marcos administration to make up for lost time and expand co-operation in ways it could have had the Philippines not elected someone like Duterte.”

Beijing has sought to convey that support for Taiwan would be risky and costly for countries in the region while encouraging governments and citizens to denounce US behaviour as provocative.

A recent video message by China’s ambassador to Singapore Sun Haiyan appealed directly to the city-state’s 5.5mn people as images of the chaotic US withdrawal from Afghanistan flashed on the screen. “Let’s speak out to those troublemakers together. No! Not here, not at our home.”

“China is laying down a fair amount of pressure to stick to Chinese talking points, especially with ‘One China’,” said William Choong, a senior fellow at Singapore’s Yusof Ishak Institute think-tank, referring to Beijing’s stance of claiming sovereignty over Taiwan.

Singapore has good relations with China and the US as well as longstanding ties with Taiwan. The neutral city-state would have to consider whether it would support US naval operations or allow American aircraft to pass through its waters and airspace if there was a conflict.

“The Chinese would immediately breathe down Singaporean necks,” Lemahieu said.

Another geographically important country is Indonesia. The country’s Panglima, or military commander, General Andika Perkasa is friendly towards the US but reaches retirement age this year.

Indonesia last month hosted the Garuda Shield war games with the US, which are held annually but were expanded to include Japan, Singapore and Australia for the first time. China, which often counters with its own drills, held exercises with Thailand’s air force at the same time.

Analysts cautioned that the Garuda Shield drills should not be taken as a sign of a step towards the US. “There was some consternation in Jakarta about how that display would play out with China. There was not universal support for it,” said one person with knowledge of government discussions.

Others said Indonesia was unlikely to pick sides or even denounce any action. “I think the conversation is leaning towards us not allowing any military ship to transit through our archipelagic waters in times of conflict, be it US or China,” said Gilang Kembara, a Jakarta-based researcher for the Centre for Strategic and International Studies think-tank.

Economic pressures are adding to the region’s worries, with the global growth outlook weakening and decoupled supply chains hitting export-reliant countries. The US has trumpeted the benefits of its Indo-Pacific Economic Framework while China has offered governments inducements, loans and other economic opportunities.

“It is increasingly difficult for [south-east Asian] countries to have their cake and eat it too,” said Chong Ja Ian, an assistant professor at the National University of Singapore. “No country has articulated what they would do in the event of conflict, but soon they may have to.”