North Korea fired the ballistic missiles, believed to be of Scud-C type, in 10 minutes from 6.19 a.m. Monday in the Gitaeryeong and Wonsan areas on the country's southeast coast, Xinhua reported citing the media.
The missiles, fired towards the northeastern waters, were believed to be of Scud-C type as they flew more than 500 km.
On Feb 27, North Korea fired four short-range missiles, allegedly of Scud-type, from the same area. The four missiles flew around 220 km at an altitude of 60-70 km.
North Korea reportedly has around 700 Scud-type missiles of 300 km-range and of Scud-C type of 500 km-range. It also has Scud-ER missiles, a modified version of Scud-D missiles, with a range of more than 700 km.
South Korea's defence ministry spokesman Kim Min-seok said that the launch was seen as "intended provocation" as the incident came after the annual war games between Seoul and Washington began.
South Korea and the US began their annual joint war games as scheduled despite North Korea's demand for the delay or cancellation of the drills.
The "Key Resolve" command post exercise and the "Foal Eagle" field training exercise started Feb 24 morning with the participation of 12,700 US soldiers, including more than 6,000 from overseas bases.
A North Korean patrol ship intruded into the disputed inter-Korean maritime border on the night of Feb 24, media reported.