Foreign Ministry spokesman Zhao Lijian said on Tuesday that China will take firm and strong measures to resolutely safeguard its sovereignty and territorial integrity if United States House Speaker Nancy Pelosi goes ahead with her plan to visit Taiwan in severe violation of the one-China principle.

"The US side must completely bear all possible consequences that arise from this visit," Zhao said at a regular news briefing in Beijing after the Financial Times said Pelosi plans to visit Taiwan next month.

The visit would be the first trip to Taiwan by a speaker of the US House of Representatives in 25 years. Pelosi canceled a trip to Taiwan in April after she was infected with COVID-19. State Councilor and Foreign Minister Wang Yi had said at that time that Pelosi's visit would be a malicious provocation against China's sovereignty.

Zhao said, "If Pelosi visits Taiwan, it would gravely violate the one-China principle and the stipulations of the three China-US joint communiques, seriously undermine China's sovereignty and territorial integrity, severely affect the political foundation of China-US relations and send a seriously wrong signal to 'Taiwan independence' separatist forces."

The spokesman urged the US to cancel the plan, stop official contact with Taiwan and fulfill its commitment, with real actions, of not supporting "Taiwan independence".

Zhu Fenglian, a spokeswoman for the Taiwan Affairs Office of the State Council, said on Tuesday that some US lawmakers have frequently been provocative in their remarks and actions on the Taiwan question recently, attempting to contain China and prevent its reunification.

She also warned that any attempts by Taiwan's Democratic Progressive Party authorities to seek "Taiwan independence" by conspiring with external forces will only end in failure.

Zhao also criticized Washington on Tuesday for increasing tensions across the Taiwan Straits after the US State Department defended on Monday its decision to approve a potential arms sale to Taiwan by citing the so-called "Taiwan Relations Act". The deal, worth $108 million, would be the fifth arms sale to Taiwan under the current US administration.

Reiterating that China strongly opposes and condemns the deal, Zhao said the so-called "Taiwan Relations Act", a US law that China has never recognized and always rejected, is no justification for the US to brazenly interfere in China's internal affairs and sell arms to Taiwan.

He said that the US arms sale to Taiwan would embolden the "Taiwan independence" separatist forces and escalate tensions across the Straits, urging the US to immediately stop arms sales to and military contact with Taiwan.

He noted that the one-China principle is the political foundation underpinning China-US relations and is also a consensus shared by the international community.

"China firmly opposes anyone or any force attempting to play the 'Taiwan card' to interfere in China's domestic affairs and harm China's core interests," Zhao said.