China is firmly opposed to the United States plan to brief the Taiwan region on the results of an upcoming meeting between President Xi Jinping and US President Joe Biden, as the move seriously violates the one-China principle and is "egregious in nature".

Foreign Ministry spokesman Zhao Lijian made the comment on Friday, pointing out that official exchanges between the US and the Taiwan region run counter to the US commitment of keeping only unofficial relations with the island.

White House National Security Adviser Jake Sullivan said on Thursday that the US would brief the Taiwan region on the results of the meeting, which the US said will take place in Bali, Indonesia, on Monday on the sidelines of the G20 Summit.

Responding to Sullivan's remarks, Zhao said the root of the current tension across the Taiwan Straits lies in the repeated attempts by the Taiwan authorities to solicit US support to seek "Taiwan independence", and in the intention of some people in the US to use the Taiwan question to contain China.

Dismissing Sullivan's mentioning of the US "commitment to the Taiwan Relations Act", Zhao said the act, which was unilaterally formulated by the US, runs counter to the principles of the three joint communiques between China and the US and the basic norms guiding international relations.

"China has been firmly opposed to the so-called act from the very beginning," the spokesman said. "The US has no right to place its domestic law above international law, let alone use it as an excuse to interfere with China's internal affairs."

Instead of following the so-called act, the US should observe the one-China principle and the three joint communiques between China and the US when it comes to the Taiwan question, Zhao said, reiterating that there is only one China in the world, and Taiwan is an inseparable part of Chinese territory.

The US should also terminate its official exchanges and military contacts with Taiwan, stop selling weapons to the region, and honor its commitment of not supporting "Taiwan independence" with concrete actions, instead of "leading China-US ties to jeopardy", Zhao said.