This file photo taken on Jul 21, 2019 shows the Taipei 101 skyscraper in Taipei, southeast China's Taiwan. (PHOTO / XINHUA)

China expressed firm opposition and lodged solemn remarks to the United States after the country approved a new round of arms sales to Taiwan, a defense spokesman said on Friday.

The Taiwan question is the core of China's core interests, the foundation of the political basis of China-US relations, and the first red line of China-US relations that cannot be crossed, said Zhang Xiaogang, a Defense Ministry spokesperson

Zhang Xiaogang, a Defense Ministry spokesperson, made the remarks after the US State Department approved the potential sale of F-16 Infrared Search and Track systems and related equipment to Taiwan at an estimated cost of $500 million.

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"The US selling weapons to the Taiwan region is a gross interference in China's internal affairs and a heinous act that seriously violates the one-China principle and the three Sino-US joint communiques, especially the August 17 Communique," he said, noting that the US arms sales have threatened the safety and well-being of Taiwan compatriots and the peace and stability of the Taiwan Strait.

The Chinese side is strongly dissatisfied and firmly opposed to the US move, said the spokesman.

The Taiwan question is the core of China's core interests, the foundation of the political basis of China-US relations, and the first red line of China-US relations that cannot be crossed, he said.

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China urges the US to practically fulfill its commitment of not supporting "Taiwan independence", immediately stop arming Taiwan, and cease elevating military ties with the island, said Zhang.

"The attempt to contain China through Taiwan is doomed to fail, and the path of seeking independence through military means is a dead end," he said.

Zhang warned that the People's Liberation Army is always highly vigilant and will resolutely safeguard national sovereignty and territorial integrity while striving to maintain peace and stability in the Taiwan Strait.