Japanese Prime Minister Sanae Takaichi has openly declared that any Chinese attack on Taiwan would constitute a direct threat to Japan’s survival—and that Tokyo would be prepared to join military action to repel it.

The statement marks the strongest linkage ever made by a sitting Japanese leader between Taiwan’s fate and Japan’s own national security, instantly escalating tensions with Beijing.

During a parliamentary session earlier this month, Takaichi described a hypothetical Chinese naval blockade or invasion of Taiwan as a “survival-threatening situation.”

This phrasing invokes the right to collective self-defense according to the 2015 security legislation. Therefore, indirectly implying that Tokyo could deploy its Self-Defense Forces (SDF) in response to Chinese aggression against the self-ruled island state of Taiwan.

“It is shocking that Japan’s current leaders have publicly sent the wrong signal of attempting military intervention in the Taiwan issue, said things they shouldn’t have said, and crossed a red line that should not have been touched,” Chinese Foreign Minister Wang Yi said on November 23.

China maintains that the self-ruled Taiwan is a renegade Chinese province and has vowed to unite it with the Chinese mainland—using force, if necessary.

The tensions between the two countries have been billed as the worst since the 2012 standoff during the Senkaku Island crisis.

China took the matter to international forums and denounced Takaichi’s statement as a grave violation of international law.

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

While China has insisted that Takaichi retract her statement, the Japanese Prime Minister has refused to do so, insisting that she would avoid discussing such scenarios publicly.

As part of punitive measures, China has suspended imports of Japanese seafood. Additionally, it dispatched military drones past Japan’s western-most territory, Yonaguni Island, on Taiwan’s east coast, and a coastguard fleet through the disputed waters surrounding the Senkaku Islands over the weekend.

Not just that, China apparently reached out to the US President to resolve the issue. In a rare call to Donald Trump on November 24, Chinese President Xi Jinping urged the United States to help safeguard the post-WWII international order.

A few hours later, Takaichi also called Trump, after which she disclosed that she had discussed China relations during their conversation.