"Now we're clear-eyed about the challenges to peace and stability in this region and worldwide," the Pentagon chief said as he met his Japanese counterpart Gen Nakatani in Tokyo.

"That includes coercive behavior by the People's Republic of China in the East China Sea and the South China Sea and elsewhere in the region," Austin said.

"It includes Russia's reckless war of choice in Ukraine, and it includes the DPRK support for Moscow's war, as well as its other destabilising and provocative activities," he added, using the initials of North Korea's official name.

Austin, who is on his 13th and likely final trip to Asia as defence secretary, said that "America's extended deterrence commitment to Japan and to the Republic of Korea is ironclad".

"We're meeting these challenges with confidence and resolve, and we remain committed to advancing our historic trilateral cooperation" with Japan and South Korea.

US President-elect Donald Trump, who will be sworn in next month, hopes to replace Austin with Pete Hegseth, a former military officer and Fox News presenter.

Nakatani said at the meeting that the regional security situation was "growing ever more severe".

The Japanese defence minister also praised Austin for the initiative he has taken in "strengthening and cementing the deterrence of the Japan-US alliance".