US defence secretary Lloyd Austin accused China of stepping up coercive behaviour towards Taiwan as he stressed that Washington would maintain its military capacity to resist any force that threatened the country.

Speaking at the IISS Shangri-La Dialogue defense forum in Singapore, Austin said China was engaging in provocative behavior across the Indo-Pacific region that ranged from dangerous naval and aerial manoeuvres to increasingly assertive military activity around Taiwan.

“We’ve witnessed a steady increase in provocative and destabilizing military activity near Taiwan,” Austin said on Saturday. “That includes PLA aircraft flying near Taiwan in record numbers in recent months.

Addressing an audience that included General Wei Fenghe, China’s defence minister, Austin said there had been an “alarming increase” in unsafe aerial intercepts and confrontations at sea by Chinese military ships and aircraft.

Austin referred to recent incidents in which Chinese air force fighter jets conducted “dangerous intercepts” in the South China Sea and East China Sea of aircraft flown by US allies — in a reference to Australia and Canada.

Speaking several weeks after President Joe Biden said in Tokyo that the US would intervene militarily to defend Taiwan from any Chinese attack, Austin said Washington would adhere to the Taiwan Relations Act by ensuring that Taiwan maintained a sufficient defense capability.

“And it means maintaining our own capacity to resist any use of force or other forms of coercion that would jeopardize the security or the social or economic system of the people of Taiwan,” he added.

Austin stressed that US policy towards Taiwan had not changed and that the administration remained opposed to any unilateral changes to the status quo across the Taiwan Strait — from Taipei or Beijing.

His comments came as US officials have grown increasingly worried about the Chinese threat to Taiwan, over which China claims sovereignty.

Austin used his speech to highlight the Biden administration’s efforts to boost cooperation with allies, including the Quad — a security group that includes the US, Japan, Australia and India — and the Aukus security pact agreed by the US, UK and Australia last year.

Paul Haenle, director of Carnegie China, a think-tank, said Austin’s speech “struck the right balance”, noting that the US defense secretary said US policy towards Taiwan had not changed while “stressing that key components of that policy are helping Taiwan maintain a sufficient self-defense capability and maintain a robust US capacity to resist any Chinese use of force”.