“China appears to be moving from a period of being content with the status quo over Taiwan to a period in which they are more impatient and more prepared to test the limits and flirt with the idea of unification,” a senior US official told the Financial Times.

The official said the Biden administration had reached the conclusion after assessing Chinese behaviour during the past two months.

“As we prepare for a period in which Xi Jinping will likely be entering his third term, there’s concern that he sees capstone progress on Taiwan as important to his legitimacy and legacy,” the official added. “It seems that he is prepared to take more risks.”

Twenty Chinese warplanes flew into Taiwan’s air defence zone on Friday, marking its biggest incursion. It came one day after the US and Taiwan agreed to boost co-operation between their coast guards.