North Korea launched what were believed to be multiple short-range cruise missiles into the sea between the Korean peninsula and Japan on Tuesday, South Korea's Joint Chiefs of Staff said, the latest in a series of weapons' tests by the reclusive state.
South Korea's military is monitoring for more developments, and South Korean and U.S. intelligence officials were conducting more analysis of the launch, the JCS said.
The missiles flew about 150km (93 miles), JCS told reporters. Several military aircraft also appeared to have been involved in the drill.
North Korea has been conducting weeks of military drills, including several launches of short-range ballistic missiles in recent weeks. Last month, it fired nine ballistic missiles in four rounds of tests, according to analysts.
On Sunday, North Korean state media reported leader Kim Jong Un had visited an airbase and observed drills by the country's fighter jets and attack aircraft.