North Korea has fired what appears to be an intercontinental ballistic missile (ICBM) towards the sea off its east coast, South Korea's military said.
The launch comes at a time of deteriorating relations between the two Koreas and Pyongyang's increasingly aggresive rhetoric towards Seoul.
The missile was fired at a sharply raised angle or lofted trajectory at about 07:10 local time on Thursday (22:10 GMT Wednesday).
South Korea had warned on Wednesday that the North was preparing to fire its ICBM around the time of the presidential election in the US on 5 November.
North Korea last fired an ICBM in December last year, in defiance of long-standing and crippling UN sanctions.
Neighbouring Japan said that it monitored Thursday's launch, adding that the missile was expected to have fallen into the sea by 08:40 local time.
Thursday's launch comes after South Korea and US accused North Korea of sending troops to Russia to support Vladimir Putin's war in Ukraine.
The alleged presence of North Korean troops in Russia has added to growing concerns over deepening ties between Putin and North Korean leader Kim Jong Un.