THE US, Japan and South Korean have begun a two-day training drill to prepare their militaries in response to North Korea's nuclear and missile threats.
“Therefore, we have to take calibrated and different responses to meet with that level of threat.”
General Mattis and Onodera were joined by South Korean Defence Minister Song Young-moo at a meeting of defence chiefs in the Philippines.
Mr Song said: “North Korea’s provocative behaviour is becoming worse and worse.”
General Mattis said the continued tests from Pyongyang “threaten regional and global security.”
The countries committed to steeping up joint air drills at the talks.
A joint statement said: “The three ministers lauded collective efforts to expand information sharing on North Korea’s nuclear and missile threats and enhance response capabilities, including the execution of multiple combined flight training missions with US bomber aircraft.
“They reaffirmed that the three nations are committed to enhancing defence cooperation and to maintaining a rules-based order.
“Accordingly, the ministers pledged to take necessary steps to bolster their ability to improve information sharing and strengthen responses to North Korean threats.”