The Joint Chiefs of Staff(JCS) said North Korea fired an unidentified projectile toward the East Sea on Tuesday morning.
The JCS announced it in a text message to reporters at around 7:30 a.m. but details have yet to be disclosed.
Military authorities are reportedly analyzing the launch, such as the range and type of projectile.
The launch comes six days after the North test-fired a ballistic missile into the East Sea from the northern province of Jagang, claiming it was a hypersonic missile.
The military usually discloses missile launches to the media quickly when it detects a ballistic missile.