China has lodged stern representation with the U.S. side over a congresswoman's visit to its Taiwan region.

Tammy Duckworth, U.S. senator and an Illinois Democrat, arrived at the Taiwan region on Monday.

Chinese Foreign Ministry spokesperson Zhao Lijian on Tuesday told a briefing in Beijing that Taiwan is a province of China, and the visit of the U.S. senator gravely violates the one-China principle and the stipulations of the three China-U.S. joint communiques.

"China firmly opposes this and has lodged stern representation with the U.S. side," said Zhao.

The Chinese side urges the U.S. side to earnestly abide by the one-China principle and the three China-U.S. joint communiques, and stop all forms of official interactions with Taiwan to avoid sending wrong signals to the "Taiwan independence" separatist forces, he said.

China will continue to take strong measures to resolutely safeguard its national sovereignty and territorial integrity, said the spokesperson.

The United States has recently accelerated its playing of the so-called "Taiwan card" by a series of attempts that violate the one-China principle, from inviting the region to participate at the World Health Assembly, to U.S. President Joe Biden's gaffe last week.

However, during a video call with the Chinese leader in March, Biden reiterated that the U.S. does not support "Taiwan independence," that it does not seek a new Cold War with China, that it does not aim to change China's system, that the revitalization of its alliances is not targeted at China, and that it has no intention to seek a conflict with China.

At the news briefing on Tuesday, Zhao said China has noted the recent series of wrong signals the U.S. government has sent on the Taiwan question.

What the U.S. government should do is to follow through Biden's commitments in March with concrete actions, he said.

Zhu Fenglian, spokesperson for the Taiwan Affairs Office of the State Council, on Tuesday also opposed any form of official contacts or military collusion between the Taiwan region and the United States.

She said the Democratic Progressive Party authority's attempts to draw in external anti-China forces to seek "Taiwan independence" are doomed to fail.