According to the South Korean military, North Korea launched an intercontinental ballistic missile which exploded in mid-flight. The North's seventh intercontinental ballistic missile (ICBM) launch of the year, which landed in the sea, set off an alarm in Japan.
Fears that the North will soon do a nuclear test are making things worse. Both Koreas fired missiles Wednesday near the waters of the other. During the exchange, the North fired the most missiles in a single day.
The US and South Korea are holding their biggest-ever joint air drills, which Pyongyang has called "aggressive and provocative." At the same time, North Korea has launched multiple rockets.
South Korea's Joint Chiefs of Staff said that North Korea fired a long-range missile on Thursday at about 7:40 local time (23:40 GMT). The BBC was told by a source that it was an ICBM.
It flew about 760 km (472 miles) and got up to about 1,920 km in the air. But South Korea's military said that the launch was "presumed to have ended in failure." Pyongyang also fired two ballistic missiles with a short range.
Because of the launches, the Japanese government told people in some of the country's northern regions to stay inside on Thursday morning, which is rare.
Tokyo said at first that the missile had flown over Japan, but later the Defense Minister Yasukazu Hamada said it "did not cross the Japanese archipelago and disappeared over the Sea of Japan."
Later, Japan's Prime Minister Fumio Kishida called North Korea's "repeated missile launches" a "outrage."
The US said that the launch showed how dangerous North Korea's missile program is to its neighbors and to peace and security around the world.
A spokesman for the State Department said, "Our commitments to the defence of the Republic of Korea and Japan remain ironclad."
During a phone call on Thursday, South Korea's Vice Foreign Minister Cho Hyun-dong and the US's Deputy Secretary of State Wendy Sherman called the launches "deplorable and immoral."
The official North Korean flag
After the ICBM launch, the US and South Korea agreed to keep going with their joint air drills even though they were supposed to end on Friday.
It happened less than a month after North Korea fired a ballistic missile over Japan for the first time in five years. As tensions have risen, the North has tested a record number of missiles this year.
Even though sanctions were very tough, Pyongyang did six nuclear tests from 2006 to 2017 and is thought to be planning a seventh.
It has kept improving its military, even though it is against UN Security Council resolutions, in order to threaten its neighbors and maybe even be able to attack the US mainland.
One of Pyongyang's ballistic missiles flew over the Northern Limit Line (NLL), which is a disputed maritime border between the two Koreas. It didn't land in South Korea's waters, but it was the closest a North Korean missile ever got to the border.
In response, Seoul's warplanes fired three air-to-ground missiles that also crossed the disputed maritime demarcation line. It sent 23 missiles into the air on Wednesday.
Kim Jong-dae, a visiting scholar at the Yonsei Institute for North Korean Studies, says that they were sent off from different places all over the country.
He spoke to YTN, a local news station saying:
South Korea and the US believe that if they find the starting point of the provocation, they can precisely strike it. But there are starting points all over North Korea, and North Korea is posing multi-dimensional, systematic and simultaneous threats that they can fire (missiles) anywhere in their land. This is a situation which I've seen for the first time.- Kim Jong-dae, a visiting scholar at the Yonsei Institute for North Korean Studies
Since the end of September, North Korea has been doing more and more. A professor of North Korean studies at Ewha Woman University, Park Won-gon, said that North Korea is likely to do its seventh nuclear test to show that it has the ability and will to do so.
According to him:
It's unrealistic to expect North Korea to denuclearise, as it wants de facto nuclear state status to sit on the negotiation table with the US.- Park Won-gon, a professor at the North Korean studies at Ewha Woman University