WASHINGTON - US President Joe Biden has again said the US would defend Taiwan in the event of an attack by China. Asked in a CBS interview if US troops would defend the island, Mr Biden said: “Yes, if in fact, there was an unprecedented attack.”

The remarks prompted the White House to clarify that the official US policy - which doesn’t commit to military action on Taiwan - had not changed.

Beijing said it “deplores and firmly opposes” Mr Biden’s pledge of action.

The foreign ministry said it had lodged “stern representations” with Washington over the remarks, broadcast in a CBS 60 Minutes interview on Sunday. Taiwan is a self-ruled island off the coast of eastern China that Beijing claims as part of its territory. Washington has always walked a diplomatic tightrope over the issue.

On the one hand it adheres to the One China policy, a cornerstone of its relationship with Beijing. Under this policy, the US acknowledges that there is only one Chinese government, and has formal ties with Beijing rather than Taiwan.

But it also maintains close relations with Taiwan and sells arms to it under the Taiwan Relations Act, which states that the US must provide the island with the means to defend itself.

Mr Biden’s comments, his clearest yet in pledging US military intervention, seemingly run counter to Washington’s stance of “strategic ambiguity” - it does not commit to defending Taiwan, but also does not rule out the option.

In Sunday’s interview Mr Biden also reiterated that the US was not encouraging Taiwan independence. “There’s a One China policy and Taiwan makes their own judgements on their independence. We are not moving, not encouraging their being independent - that’s their decision,” he said.

Taiwan responded to Mr Biden’s remarks on Monday by welcoming the “US government’s rock-solid security commitment to Taiwan”. Taipei said it would continue to deepen its “close security partnership” with Washington.

Only earlier this month, the US agreed to sell $1.1bn (£955m) in weaponry and missile defence to Taiwan, provoking anger from China.