South Korea's Defense Ministry says North Korea on May 18 launched three short-range missiles off its east coast.
South Korea's Defense Ministry spokesman Kim Min-seok, speaking in Seoul, said Pyongyang fired two missiles this morning and another in the afternoon in the Sea of Japan.
North Korea last carried out missile launches in March when it test-fired two short-range missiles.
Earlier this year, North Korea threatened nuclear strikes on Seoul and Washington because of annual U.S.-South Korean military drills and UN sanctions imposed over its third nuclear test in February.
The drills ended late last month.
Min-soek said Seoul was strengthening surveillance on North Korea and remains on high alert.
Based on reporting by AP, dpa, and Reuters