North Korea fired an unidentified ballistic missile towards the sea off its east coast on Sunday, South Korea's Joint Chiefs of Staff said, ahead of large-scale planned military drills by South Korean and US forces involving an aircraft carrier.
South Korea's military did not provide further details about the missile including the range or its trajectory.
South Korea's Yonhap news agency reported on Saturday North Korea may be preparing to test a submarine-launched ballistic missile (SLBM), citing the South's military.
The launch comes after the arrival of a US aircraft carrier in South Korea to participate in joint drills with South Korean forces, and ahead of a planned visit next week by US Vice President Kamala Harris.
North Korean launch is unprecedented
It was the first time the North carried out such a launch after firing eight short-range ballistic missiles in one day in early June, which led the United States to call for more UN sanctions for violating UN Security Council resolutions.
North Korea rejects UN resolutions as an infringement of its sovereign right to self-defense and space exploration.