"Secretary Austin underscored the unwavering US commitment to the defense of Japan, including US extended deterrence provided by the full range of conventional and nuclear capabilities," Pentagon Press Secretary Brigadier General Pat Ryder said in a statement.

"The ministers affirmed that the alliance is stalwart in the face of challenges, and steadfast in support for shared democratic values and norms that underpin the rules-based international order," the statement added.

The previous day, Austin said a so-called Marine Littoral Regiment, a more agile unit that can operate defenses both by sea and air, would be in place by 2025 in Okinawa, the southern Japanese island strategically close to Taiwan.

Japan has been officially pacifist since its defeat in World War II but has increasingly shed past sensitivities as China exerts itself and North Korea keeps firing missiles, some of them over Japanese territory.

The government of Prime Minister Fumio Kishida, who is due to visit Washington on Friday, said last month that Japan would increase defense spending by 2027 to two percent of GDP.