North Korea has fired what has been described as an unidentified projectile into the sea, said South Korea’s Joint Chiefs of Staff.
The Japanese coast guard, which first reported the launch, said it could potentially be a ballistic missile, but no confirmation has yet been given.
The UN prohibits North Korea from ballistic and nuclear weapons tests.
If confirmed, this would be the first such launch carried by Pyongyang this year.
Ballistic missiles are considered more threatening than cruise missiles because they can carry more powerful payloads, have a longer range and can fly faster.