BEIJING: China has taken its widening spat with Japan to the United Nations, accusing Tokyo of threatening “an armed intervention” over Taiwan and vowing to defend itself in its strongest language yet in the two-week-old dispute.

Japanese Prime Minister Sanae Takaichi committed “a grave violation of international law” and diplomatic norms when she said a Chinese attack on Taiwan could trigger a military response from Tokyo, China’s UN Ambassador Fu Cong wrote in a letter on Friday to UN Secretary-General Antonio Guterres.

“If Japan dares to attempt an armed intervention in the cross-Strait situation, it would be an act of aggression,” Fu wrote, according to a statement from China’s UN mission. “China will resolutely exercise its right of self-defense under the UN Charter and international law and firmly defend its sovereignty and territorial integrity.”

Biggest bilateral crisis in years

Beijing views democratically governed Taiwan as its own territory and has not ruled out the use of force to take control of the island. Taiwan’s government rejects Beijing’s claims and says only the island’s people can decide their future.