China opposed and condemned the United States on Monday for lifting restrictions on official contacts with Taiwan, saying it will resolutely fight back over any attempts to sabotage China's core interests.

The Taiwan question is the most important and sensitive part of China-US relations, Foreign Ministry spokesman Zhao Lijian said at a news briefing.

China allows no individual or force to obstruct its reunification process, he said, adding that it also allows no attempt to interfere in China's internal affairs under the pretext of the Taiwan question, Zhao said.

Mike Pompeo, the US secretary of state, said on Saturday that the US would lift "self-imposed restrictions" that have governed relations with Taiwan. Pompeo said all "contact guidelines" should be considered "null and void".

The decision was announced a day after the US said Kelly Craft, its ambassador to the United Nations, would visit Taiwan this week despite China's opposition.

The US government made solemn pledges on the Taiwan question to China in the joint communiques marking the establishment of bilateral diplomatic ties, Zhao said.

According to the communiques, the US recognizes the government of the People's Republic of China as the sole legal government of China, and within this context, the people of the US will maintain cultural, commercial and other unofficial relations with the people of Taiwan.

Washington should not use any excuses to distort or deviate from the pledge, Zhao said, urging the US to abide by the one-China principle and the three China-US joint communiques, instead of the Taiwan Relations Act manufactured by the US unilaterally.

The one-China principle is the political bedrock of China-US ties, as well as a prerequisite for the two nations to establish and develop bilateral relations, Zhao said.

"We urge the US to stop making any moves to elevate its relations with Taiwan or strengthen its military ties with the island," he said, adding that the US should stop manipulating the Taiwan question and refrain from taking any more wrong steps.

Zhu Fenglian, a spokeswoman for the Taiwan Affairs Office of the State Council, said on Monday that by relying on the US to seek "independence", the ruling Democratic Progressive Party authorities are willing to act as a pawn, which will only bring deep disaster to the island.

China will take resolute countermeasures against any collusion between the island and the US, Zhu said.

Pompeo has been playing the Taiwan card to erode the foundation of China-US ties, which aims to create a fierce confrontation between the two countries, said Li Haidong, a professor of US studies at China Foreign Affairs University.

"Such practices harm others without benefiting themselves," he said.