The South Korean military said that North Korea test-fired a ballistic missile toward the sea to the east of the Korean Peninsula in the early hours of the New Year.
The move comes not even 24 hours after North Korea launched three ballistic missiles on Saturday.
North Korea also launched three ballistic missiles on Saturday, according to South Korea's Joint Chiefs of Staff.
The short-range ballistic missile was fired around 2:50 a.m. local time (0750 GMT) from Pyongyang, Yonhap said, citing South Korea's Joint Chiefs of Staff.
The launch follows an unprecedented number of missile tests conducted by North Korea this year, as Pyongyang presses on with weapons development amid speculation it could test a nuclear weapon for the seventh time.
