A Chinese defense spokesperson on Tuesday expressed strong opposition to and condemnation of a visit to Taiwan by members of the U.S. Congress who arrived in a military airplane.

"The U.S. act has wantonly interfered in China's internal affairs, seriously undermined China's territorial sovereignty and posed a severe threat to peace and stability in the Taiwan region," Tan Kefei, spokesperson for China's Ministry of National Defense, said while reiterating that Taiwan is a sacred and inalienable part of Chinese territory.

"We sternly warn that the United States must immediately stop its provocative actions and all destructive moves that lead to the further escalation of tensions in the Taiwan region, and refrain from sending false signals to 'Taiwan independence' separatists," Tan said.

Taiwan's Democratic Progressive Party authority must not misjudge the situation or take desperate moves, which will only bring disaster to Taiwan, Tan warned.

China must be and will be reunited, he stressed.

"No one should underestimate the Chinese people's staunch determination, strong resolve and powerful capability to defend national sovereignty and territorial integrity," Tan said, adding that the People's Liberation Army remains on high alert and will take every necessary measure to crush any external interference or any form of separatist attempts for "Taiwan independence."