South Korea's Joint Chiefs of Staff (JSC) said it detected the launches from the Chunghwa County area in North Hwanghae Province between around 7:47 a.m. and 8 a.m, Yonhap news agency reported.

The missiles flew some 370 kilometers before splashing into the sea, it added.

Pyongyang's latest provocation came as South Korea and the United States kicked off the Ssangyong (double dragon) amphibious landing exercise last week, the South Korean news agency reported.