Japan defence minister says US, SKorea cooperation 'critical' for security

Japan's defence minister said on Tuesday that cooperation with South Korea and the United States was "critical" to regional security, after US President Donald Trump seeded doubts in the Pacific region by downsizing joint drills with Seoul.

Speaking on a visit to Australia, Shinjiro Koizumi came out strongly in support of joint security cooperation with its key defence backer Washington, and neighbour Seoul.

"As Japan faces the most severe and complicated security environment in the post-war era, the cooperation among Japan, the United States and South Korea is critical to the peace and stability of the region," Koizumi told journalists.

The Japan-Australia meeting in Canberra came hours after Trump praised his relationship with North Korean leader Kim Jong Un and lashed out at the South for not helping Washington fight Iran.

Asked about Trump's comments, Australian Defence Minister Richard Marles said his country was "very concerned about North Korea's nuclear programme as well as its missile programme, and we have consistently made that point".

"I think in the challenging world that we face... and there are many challenges, but North Korea is the author of quite a few of those challenges," he added.