South Korea's military says the North has fired a ballistic missile.
The U.S. Defense Department said it was still assessing the "probable" missile launch on November 28.
The South Korean Joint Chiefs of Staff said North Korea launched a ballistic missile at around 6.17 p.m. Greenwich Mean Time from Pyongsong in South Pyongan Province over the sea between South Korea and Japan.
Seoul says it responded to the launch with a missile-firing test.
South Korea and the United States are currently analyzing what type of missile was fired, the military said.
It was not clear how far the missile went and whether it flew over Japan.
Pyongyang test fired several missiles this year, including intercontinental ballistic missiles, and carried out its sixth nuclear explosion.