A carefully planned summit between Joe Biden and Xi Jinping took a tense turn hours after their meeting when the US President referred to his Chinese counterpart as a "dictator".

The term, which Biden has now used against Xi for the second time, didn't go down well with China, who called it "extremely absurd and irresponsible."

At the same time, China ratcheted up its aggressive stance on Taiwan in the backdrop of the meeting, vowing to be "unstoppable in eventually retaking" the island nation.

Biden's remarks and China's belligerence vis-a-visa Taiwan have underscored the palpable tensions weighing on both the sides even as they try to make progress on several issues.

Addressing a solo press conference after a four-meeting with the Chinese President, Biden indicated that he had not changed his view that Xi was effectively a dictator.

"Look, he is. He's a dictator in the sense that he's a guy who runs a country that is a communist country that's based on a form of government totally different than ours," Biden said, when asked whether he still held the view.

The remark again outraged China, which strongly opposed it without naming Biden.

At the same time, China ratcheted up its aggressive stance on Taiwan in the backdrop of the meeting, vowing to be "unstoppable in eventually retaking" the island nation.

Biden's remarks and China's belligerence vis-a-visa Taiwan have underscored the palpable tensions weighing on both the sides even as they try to make progress on several issues.

Addressing a solo press conference after a four-meeting with the Chinese President, Biden indicated that he had not changed his view that Xi was effectively a dictator.

"Look, he is. He's a dictator in the sense that he's a guy who runs a country that is a communist country that's based on a form of government totally different than ours," Biden said, when asked whether he still held the view.

The remark again outraged China, which strongly opposed it without naming Biden.

(With inputs from agencies)