The Pentagon said it had detected a "probable" missile launch and that it was in the process of assessing it.
ADVERTISEMENTNorth Korea fired an intercontinental ballistic missile that landed close to Japan, US government sources believe.
Japan's Prime Minister Shinzo Abe said that North Korea's missile launch "could not be tolerated."
Both the South Korean and Japanese governments convened an emergency national security council meetings.
The Pentagon said the missile traveled 998 kilometres and reached a height of about 4506 kilometres before plunging into the Sea of Japan.
David Wright, co-director of the global security program at the Union of Concerned Scientists, said in a blog post that If the missile had flown on a standard trajectory rather than the lofted trajectory, it would have a range of more than 13,000 kilometres, which is "significantly longer" than any of North Korea's previous long range tests.
However, Wright pointed out that it is unlikely that North Korea is capable of delivering a nuclear warhead to this long distance.
President Donald Trump said the US would not change its approach and that it would take care of the issue.
"We will take care of it, said President Donald Trump, it is a situation we will handle."
Meanwhile, US Defence Secretary James Mattis said the missile went higher than any had done previously.
US Secretary of State, Rex Tillerson, condemned the missile launch in a statement.
North Korea has test-fired several other missiles this year as tensions increase over the country’s nuclear programme.
It has seen a war of words between US president Donald Trump and Kim Jong-un, with the former calling the latter ‘rocket man’.