China has escalated its diplomatic confrontation with Japan by issuing a further formal complaint to the United Nations over remarks by Prime Minister Sanae Takaichi concerning Taiwan. Beijing’s ambassador to the UN, Fu Cong, submitted a second letter to Secretary General António Guterres on December 1 intensifying a dispute that has deepened since early November, Kyodo News reports.

The latest communication challenges Japan’s response delivered on November 24 by its UN ambassador, Kazuyuki Yamazaki, and accuses Tokyo of advancing unfounded arguments in defence of Takaichi’s comments. The prime minister had indicated during a parliamentary exchange on November 7, that a potential attack on Taiwan could constitute an existential threat to Japan, a view that Beijing has seized upon as evidence of what it describes as Japan’s expanding military ambitions.

According to Kyodo, Fu’s letter builds on an earlier message sent on November 21, and warns that the international community should be alert to what China characterises as Japan’s efforts to broaden its defence posture and return to a more assertive security role. The exchange marks a further deterioration in relations at a time when Beijing has stepped up military operations around Taiwan, which it regards as part of its territory and has not ruled out taking by force.

Tokyo has pushed back strongly. Chief Cabinet Secretary Minoru Kihara dismissed China’s accusations, describing them as entirely without basis and insisting that Japan has consistently acted as a stabilising force in international affairs since the end of the Second World War.

In his reply to the UN secretary general, Yamazaki reaffirmed that Japan’s security strategy remains strictly defensive and rejected China’s claim that Tokyo intends to exercise self-defence rights absent an armed attack. He also emphasised that Japan’s approach to Taiwan has remained unchanged since the establishment of diplomatic relations with China in 1972, and reiterated Tokyo’s expectation that cross-strait issues should be settled peacefully through dialogue.

The exchange underscores mounting tensions in the region as China expands military activity around Taiwan and Japan recalibrates its defence policies in response to a more volatile security environment.