"No one should underestimate the strong resolve, determination and capability of the Chinese people to safeguard national sovereignty and territorial integrity," said Chinese Foreign Ministry spokesperson Wang Wenbin, urging the US to not "stand against the 1.4 billion Chinese people".
"We urge the US side to earnestly abide by the one-China principle and the three China-US joint communiques, be cautious in words and deeds on the Taiwan question, and refrain from sending any wrong signals to secessionists, so as not to seriously damage China-US relations and peace and stability across the Taiwan Straits," Wang said.
The US would come to Taiwan's defence if the island faces a Chinese mainland "incursion," US President Joe Biden confirmed on Thursday. The strongest comments from the 78-year-old leader were believed as challenging Chinese mainland's redline and also deviating from Washington's "strategic ambiguity" on the Taiwan question.
The White House attempted to clarify Biden's comments to calm the situation, saying the President was "not announcing any change in our policy and there is no change in our policy.
Asked in a CNN town hall meeting on Thursday night about whether the US would protect Taiwan if China attacked, Biden said: "Yes," and the US has "a commitment to do that," US media reported.
Biden's comments came amid rising tension in the Taiwan Straits, with EU Parliament lawmakers pushing forward a resolution to deepen so-called political and economic ties with the island of Taiwan and the Biden administration's pick for ambassador to China vowing to make the island "a tough nut to crack", Global Times reported.
Observers said the overall US policy toward the Taiwan question is becoming clearer, and that China should not interpret some of the US moves seeking cooperation with China as signs of softening, the report added.