North Korea's attempt to launch a missile near the city of Wonsan has reportedly failed, according to the US and South Korean militaries.
The US military has reported that the missile exploded immediately after it was launched.
The test-firing follows a recent rocket engine testing by North Korea, according to media sources.
US Pacific Command spokesman commander Dave Benham said: "US Pacific Command detected what we assess was a failed North Korean missile launch attempt ... in the vicinity of Kalma.”
Commenting on the test-firing, a South Korean military official was quoted by Reuters as saying: "It may have exploded right after it took off from a launch pad.”
The South Korean defence ministry is investigating the type of the missile, which is believed to have been launched in response to the bilateral exercise the country is conducting with the US, Reuters reported.
The exercise aims to improve interoperability between the South Korean and US navies and help both forces to protect South Korea from future unprovoked acts of aggression from North Korea.
During the exercise, the navies will conduct routine bilateral training, subject matter expert exchanges, anti-submarine and anti-surface warfare drills, communication drills, air defence exercises, counter-mine planning, and distinguished visitor embarkations.