Japan says North Korea threat more serious than 'ever before'

In its annual white paper -- a rundown of the most pressing military threats and plans to ensure stability -- Japan's defence ministry made a case for a significant hike in domestic defense spending as the world enters "a new era of crisis".

"North Korea's military activities pose an even more grave and imminent threat to Japan's national security than ever before," the document said.

"It is believed that North Korea has the ability to attack Japan with nuclear weapons fitted to ballistic missiles."