North Korea fired what appeared to be two cruise missiles into the sea off its east coast on Tuesday, South Korea's Joint Chiefs of Staff said, days after a flurry of ballistic missile tests.
South Korea's military is assessing the launches to determine the nature of the projectiles, it said.
Such a launch would be its fifth missile test of the year, as North Korean leader Kim Jong Un has vowed to bolster the military with cutting-edge technology at a time when talks with South Korea and the United States have stalled.
The isolated nation's biggest flurry of missile launches since at least 2019 has prompted an expression of concern from the UN secretary-general, and the Biden administration has applied new sanctions.
Cruise missile launches by the North are not banned under United Nations sanctions imposed on Pyongyang, which has defied international condemnation and conducted four rounds of ballistic missile tests, the most recent on Jan. 17.
China and Russia have pushed the U.N. Security Council to remove a ban on Pyongyang's exports of statues, seafood, and textiles, and raise a refined petroleum imports cap.
North Korea has said it is open to talks, but only if the United States and others drop "hostile policies" such as sanctions and military drills.