Philippine President Ferdinand Marcos Jr has warned China not to cross a red line in the South China Sea, where a standoff between the countries continues to escalate.

If any Filipino died as a result of China’s wilful actions, he said on Friday, the Philippines would consider it as close to “an act of war” and respond accordingly.

Mr Marcos was speaking at a security forum in Singapore attended by defence chiefs from around the world, including the US’s Lloyd Austin.

He stressed the region remained a main focus for Washington, and that the US was only secure if Asia was too.