The launch comes days after North Korea tested a suspected ICBM in the Sea of Japan.
North Korea fired a ballistic missile at sea off the eastern coast of the Korean peninsula, Yonhap news agency reported, citing South Korea’s Joint Chiefs of Staff (JCS).
The JSC did not immediately provide details on Sunday’s launch.
The Japanese Coast Guard also said what was fired by North Korea could be a ballistic missile.
The launch comes after North Korea fired a suspected intercontinental ballistic missile (ICBM) into the sea between the Korean peninsula and Japan on Thursday, hours before the South Korean president was due to travel to Tokyo for a summit that took discussed ways to counter their nuclear-armed neighbour.
North Korean state media described the launch of Hwasong 17 as a response to ongoing “frenzied” joint exercises by South Korea and the United States.
Seoul and Washington have stepped up security cooperation after a year of record-breaking North Korean weapons tests and nuclear threats.
Pyongyang sees all these drills as rehearsals for the invasion.
Last year, North Korea declared itself an “irreversible” nuclear power and leader Kim Jong Un recently called for an “exponential” increase in the production of weapons, including tactical nuclear weapons.
