NATO Secretary-General Mark Rutte kicked off a two-day trip to Japan on Tuesday with visits to Yokosuka Naval Base and Mitsubishi Electric Kamakura Works in Kanagawa Prefecture — a move that highlights the military alliance's push to expand its partnership with Tokyo, particularly in the field of military-industrial ties.

“China is building up its armed forces, including its navy, at a rapid pace, so we cannot be naive and we really have to work together to assess what is happening,” he said at the Yokosuka base.

One of the focal points of the visit, Rutte said, is to explore ways to ramp up cooperation with the alliance’s four Indo-Pacific partners (IP4): Japan, South Korea, Australia and New Zealand.