The missile was launched "within the last 90 minutes," Colonel Rob Manning, a Pentagon spokesman, said today.
"We assess North Korea conducted a missile launch within the last 90 minutes. We can confirm that the missile launched by North Korea flew over Japan," Manning added, cautioning that the United States was still assessing the launch.
However, North American Aerospace Defense Command (NORAD) "determined the missile launch from North Korea did not pose a threat to North America," Manning said.
It travelled around 1,700 miles (2,700 kilometers) at a maximum altitude of around 350 miles, it said, adding that South Korea and the US were "closely analysing for more details.