The United States and Japan on October 23 opened a 10-day joint exercise with the participation of 45,000 soldiers from both countries across Japan focusing on air defense and missile defense.

The exercise, called Keen Sword 25, will last until November 1 with 40 ships and 370 aircraft, along with some forces from Australia and Canada, according to AFP citing information from the Japanese Joint Chiefs of Staff.

Held every two years, the exercise takes place across Japan, including military bases of the two countries.

"We have a strong sense of urgency that we cannot rule out the possibility of a serious situation like Ukraine occurring in areas close to our country," said General Yoshihide Yoshida, chief of the Japanese Joint Staff.

“We are determined to prevent and deter such a situation,” he told a news conference, adding that the US-Japan alliance was integral to regional stability.

"Keen Sword will ensure we maintain our advantage against those who seek to undermine the rules-based international order," Admiral Steve Koehler, commander of the US Pacific Fleet, told reporters.

A spokesman for the Japan Self-Defense Forces (JSDF) said the exercise would see Ospreys fly to Yonaguni, the Japanese island closest to Taiwan, for the first time, as part of an “evacuation” exercise.

The drill was aimed at practicing evacuating residents and tourists "in the event of a natural disaster," the spokesman said.