Beijing has gone on the offensive over challenges made by Donald Trump’s administration to its claims in the South China Sea, asserting its “indisputable sovereignty” in the region and warning the US to “act cautiously”.

The remarks came after White House spokesman Sean Spicer signaled a break from Washington’s cautious approach to China’s assertiveness during Barak Obama’s presidency by vowing that the US would “defend” its interests in the resource rich, strategically-important waters.

"The US is going to make sure that we protect our interests there," Mr Spicer said, when asked about islands that China is building in the South China Sea.

“If those islands are, in fact, in international waters and not part of China proper, yeah, we'll make sure we defend international interests from being taken over by another country," he said, without giving further details.