President Barack Obama pledged a "steadfast" commitment to defend Japan, including preventing nuclear attacks on its ally in the wake of North Korea's third nuclear test.
In a telephone call, Obama and Japanese Prime Minister Shinzo Abe discussed steps to respond to the "highly provocative violation of North Korea's international obligations.
Pyongyang triggered international outrage on Tuesday by carrying out its latest nuclear detonation in defiance of UN Security Council resolutions.
Follow US
Most Viewed Stories
