Japan is seriously worried about China-Taiwan tensions. In unusually blunt terms, Tokyo has warned that the military posturing by Beijing and Washington over Taiwan posed a threat to its security.

Japan’s defence ministry said the country needed to “pay close attention to the situation with a sense of crisis more than ever before.” In particular, the ministry noted that “the overall military balance between China and Taiwan is tilting to China’s favor, and the gap appears to be growing year by year.”

The comments suggest that Japan may be inching closer to Washington, which has long urged it to confront Beijing’s rising military aggression around the region. But there are differing views within the Japanese establishment on taking on China over Taiwan, and these have become public in recent weeks as well.

Over the past year, China has repeatedly flown military aircraft into Taiwan’s air defense identification zone. In response, the US sailed ships through the Taiwan Strait. Taiwan lies close to the southern Japanese island of Okinawa.