North Korea has fired an unidentified missile from the Sunan district in its capital, Pyongyang, with the missile passing over Japan.
The Japanese government said the missile had passed over Hokkaido and the country's military did not try to shoot it down.
They issued a nationwide alert - but particularly told residents in the country's north to take shelter.
The South Korean and US militaries are analysing details of the launch.
This is a developing story.
American university student Otto Warmbier imprisoned in North Korea has been medically evacuated in a coma, according to his parents.
Mr Warmbier, 22, is due to arrive home in Cincinnati on Tuesday evening, after a stop at a US military facility in Sapporo, Japan.
The UN Security Council has unanimously condemned North Korea's latest missile test and warned of new sanctions.
In a statement, the 15-member Council demanded that Pyongyang conduct no further such tests.
North Korea earlier said the missile it had tested on Sunday was a new type of rocket capable of carrying a large nuclear warhead.
The missile travelled some 700km (435 miles), reaching an altitude of 2,000km and landing in the sea west of Japan.
North Korea said it was a test of the abilities of a "newly developed ballistic rocket".
North Korea announced Monday that it successfully tested a “newly-developed ballistic rocket capable of carrying a large-size heavy nuclear warhead,” deepening fears that Kim Jong Un could one day have a weapon capable of hitting the United States.
The test launch Sunday, the tenth so far in 2017, involved a “ground-to-ground medium long-range strategic ballistic rocket Hwasong-12,” according to North Korea’s state media agency KCNA.
North Korea accused the CIA of plotting to kill supreme leader Kim Jong-un with a "bio-chemical" attack yesterday, as it threatened to "mercilessly destroy" US and South Korean intelligence agencies.
A spokesman for the secretive regime claimed that a "terrorist group" supported by the CIA attempted to poison Mr Kim in April, according to Yonhap News.
North Korea's failed missile was reportedly heading towards Russia before it was detonated mid-flight.
US officials said a medium-range ballistic missile was fired from a region north of the capital of Pyongyang and disintegrated minutes after launch.
The missile was likely to be a medium-range KN-17 ballistic missile, they added, which broke up and fell into the Sea of Japan and did not leave North Korean territory.
The Seoul Economic Daily reports the missile travelled 48 kilometres before officials detonated it over fears it was fired at Russia by accident.
Tensions in the Korean peninsula have been running high for weeks, with signs the North may be preparing a long-range missile launch or a sixth nuclear test.
Washington has refused to rule out a military strike against the dictatorship in response to any attacks, while a North Korean spokesman has said that they are, “fully ready to respond to any option taken by the US.”
North Korea said on Sunday it was ready to sink a U.S. aircraft carrier to demonstrate its military might, in the latest sign of rising tension as U.S. President Donald Trump prepared to call the leaders of China and Japan.
The United States ordered the USS Carl Vinson carrier strike group to sail to waters off the Korean peninsula in response to mounting concern over the North's nuclear and missile tests, and its threats to attack the United States and its Asian allies.
Four warships Donald Trump claimed were being sent to North Korea last week, were in fact steaming in the opposite direction to take part in military exercises with the Australian Navy over 3,500 miles away.
The USS Carl Vinson aircraft carrier and three other ships in its fleet, which Mr Trump described as an “armada”, were said to have been deployed to the Sea of Japan as a “show of force” in response to North Korea’s missile tests, military officials said on April 8.
Japan is getting ready to send several destroyers from Japan’s maritime self-defence forces to join the US aircraft carrier, Carl Vinson.
The US warship is heading to the Korean peninsula, trying to deter North Korea from conducting further missile and nuclear tests while China tries to stop them from continuing.
This comes as the Chinese president, Xi JingPing, had a phone conversation with US President Donald Trump, trying for de-escalation and a more “peaceful” approach toward North Korea.