The Taiwan question concerns China's sovereignty and territorial integrity. It is the political foundation of China-Japan relations and a red line that must not be crossed, a Chinese Foreign Ministry spokesperson said on Thursday.

Spokesperson Lin Jian made the remarks at a regular press conference in response to relevant questions from a reporter about a Japanese Maritime Self-Defense Force destroyer sailing through the Taiwan Straits for the first time.

"The Chinese military has handled in accordance with laws and regulations the entering into the Taiwan Straits of a Japanese Maritime Self-Defense Force vessel. China is highly vigilant on Japan’s political intention behind this move and has protested to the Japanese side," Lin said.

Japan made a clear commitment on this in the 1972 China-Japan Joint Statement, which says, "The Government of Japan recognizes the Government of the People's Republic of China as the sole legal Government of China. The Government of the People's Republic of China reiterates that Taiwan is an inalienable part of the territory of the People's Republic of China. The Government of Japan fully understands and respects this position of the Government of the People's Republic of China, and it firmly maintains its position under Article 8 of the Potsdam Proclamation," Lin added.

"We urge Japan to honor its commitment, act prudently on the Taiwan question and refrain from causing disruption to its relations with China and peace and stability across the Taiwan Straits," the spokesperson noted.