South Korea's Defence Ministry said on Wednesday that North Korea failed in its test-firing of a missile that was believed to have exploded in the air, a media report said.

A South Korean Defence Ministry official said via phone that North Korea fired one missile near the Wonsan airfield on its eastern coast and it was estimated to have failed, media reported.

According to local media reports, the missile exploded in the air right after blasting off from the ground.

The test-firing was an apparent show of force toward the ongoing US-South Korea military exercises, codenamed Key Resolve and Foal Eagle.   

The Foal Eagle fielding training exercise, which started off from March 1, is scheduled to continue by the end of April, with the Key Resolve command post exercise set to end on Friday.

Pyongyang has denounced the springtime war games as a dress rehearsal for northward invasion.