This was "extremely uncommon and inadmissible" as it had fallen near "regional waters south of As far as possible Line interestingly" since the landmass was isolated, said Kang Shin-chul, overseer of tasks for the Joint Heads of Staff.
That rocket had arrived in waters 26km (16 miles) south of the outline line, 57km east of the South Korean city of Sokcho and 167km north-west of Ulleungdo island.
The two nations had recorded the rockets not long before 090 (000 GMT) on Wednesday, including the one which penetrated As far as possible Line - the defacto oceanic boundary.