BEIJING, March 30 (Xinhua) -- China strongly protests and condemns the U.S. arrangement for the so-called "transit" of Taiwan leader Tsai Ing-wen through the United States, a Foreign Ministry spokesperson said on Thursday, adding that China will resolutely safeguard its sovereignty and territorial integrity.

Spokesperson Mao Ning made the remarks at a daily news briefing in response to an inquiry about Tsai's so-called stopover in the United States.

Mao said China firmly opposes any form of official interaction between the United States and the Taiwan region.

"We firmly oppose any visit by leader of the Taiwan region to the United States in any name or under whatever pretext, and we firmly oppose the U.S. government having any form of official contact with the Taiwan region," she said.

Mao noted that in disregard of China's strong demarches and repeated warnings, the United States insisted on arranging the so-called "transit" for Tsai to go to the country.

"China strongly protests and condemns that," Mao said.

She pointed out that the United States and the Taiwan authorities made arrangements for Tsai to engage in political activities in the United States and framed it as a "transit" to upgrade official exchanges and substantive relations with the Taiwan region.

"This seriously violates the one-China principle and the three China-U.S. joint communiques, gravely undermines China's sovereignty and territorial integrity and sends a seriously wrong message to 'Taiwan independence' separatists," she said.

"This once again shows that the fundamental cause of the new round of tensions in the Taiwan Strait is the Taiwan authorities' repeated attempts to solicit U.S. support for 'Taiwan independence' and the fact that some in the United States intend to use Taiwan to contain China," said the spokesperson.

Mao stressed that the Taiwan question is the very core of China's core interests, the bedrock of the political foundation of China-U.S. relations, and the first red line that must not be crossed in the relationship.

"We urge the United States to abide by the one-China principle and the three China-U.S. joint communiques, act on its commitment of not supporting 'Taiwan independence' or 'two Chinas' or 'one China, one Taiwan,' stop all forms of official interaction with Taiwan, stop upgrading its substantive exchanges with the region, and stop fudging and hollowing out the one-China principle," Mao said.

"China will continue to closely follow the situation and resolutely safeguard its sovereignty and territorial integrity," she added.