Beijing on Monday said it was ready to defend its national interests over Taiwan, in a rebuke to US President Joe Biden’s vow to protect the island from any invasion by China.

China’s Communist Party has never controlled self-ruled Taiwan but it views the island as part of its territory and has vowed to one day seize it, by force if needed.

Biden, who is in Tokyo to meet regional allies, earlier on Monday warned that China’s increasingly assertive stance over the island was “flirting with danger” and promised to defend Taiwan from any military action by its giant neighbour.

The comments were met with defiance in Beijing, with foreign ministry spokesman Wang Wenbin telling reporters “Taiwan is an inalienable part of China’s territory”.

“The Taiwan issue is a purely internal affair for China,” he said.

“On issues touching on China’s core interests of sovereignty and territorial integrity, China has no room for compromise or concession.”

Biden made a connection between the response of Western nations to Russia’s assault on Ukraine and Beijing’s perception of the risks of military action against Taiwan.

But Wang said China would always defend its interests with the force of its 1.4 billion population.

“No one should underestimate the firm resolve, staunch will and strong ability of the Chinese people in defending national sovereignty and territorial integrity,” he added.