China's envoy to the United Nations on Friday submitted a letter to UN Secretary-General Antonio Guterres detailing Beijing's position on what it calls "erroneous and dangerous" remarks made by Japanese Prime Minister Sanae Takaichi about Taiwan, according to the Chinese mission to the UN.

In the letter, China's Permanent Representative to the United Nations Fu Cong said Takaichi's recent comments in Japan's Diet "blatantly made provocative remarks on Taiwan," drawing what he described as an unprecedented link between a potential contingency in Taiwan and Japan's own security.

"This is the first time since Japan's defeat in 1945 that a Japanese leader has in an official setting advocated the notion that 'a contingency for Taiwan is a contingency for Japan,'" Fu wrote.

Fu said the remarks also marked "the first time Japan has expressed ambitions to intervene militarily in the Taiwan question" and "the first time Japan has issued a threat of force against China." He called the comments "gravely erroneous and extremely dangerous," adding that they carry "a profoundly malicious nature and impact."

According to the letter, China raised the issue repeatedly with Japan through diplomatic channels. "Despite China's repeated demarches and protests, the Japanese side refuses to repent or retract its wrongful statements," Fu wrote. "China expresses strong dissatisfaction and resolute opposition."

Fu said Takaichi's statement "constitutes a grave violation of international law and the basic norms governing international relations," arguing that it could "seriously undermine the post-war international order" and cause concern among "the peoples of other Asian countries that once suffered from Japanese aggression."

Reaffirming Beijing's position on Taiwan, Fu wrote: "Taiwan is China's sacred territory. How to resolve the Taiwan question is a matter for the Chinese people and brooks no foreign interference." He warned that any move by Japan to involve itself militarily would be considered unacceptable by China. "If Japan dares to attempt an armed intervention in the cross-Strait situation, it would be an act of aggression," he said.

Fu added that China would "resolutely exercise its right of self-defence under the UN Charter and international law and firmly defend its sovereignty and territorial integrity."

In the letter, Fu urged Japan to "deeply reflect upon its historical crimes," saying that as a country defeated in World War II, Japan "must strictly honor its political commitment on the Taiwan question, immediately stop making provocations and crossing the line, and retract its erroneous remarks."

The Chinese mission said the letter will be circulated to all UN member states as an official document of the General Assembly.