North Korea fired two short-range missiles off its eastern coast early Sunday morning, the second such launch in less than a week.
South Korea's Joint Chiefs of Staff said the weapons fired were Scud missiles that flew about 500 kilometers from the vicinity of Wonsan into the East Sea.
An official from the Joint Chiefs of Staff said North Korea did not give any prior warning of the launch for civilian flights or vessels.
The South Korean military believes the missiles to be Scud-C or Scud-ER missiles.
Scud missiles are liquid propellant ballistic missiles that have a range covering the whole of the Korean peninsula.
North Korea has fired 11 short-range missiles this year and Sunday's launch marks its fourth ballistic missile launch.
In February, it fired four ballistic missiles believed to be Scud B missiles, and in March it launched two missiles presumed to be Scud C or Scud ER missiles into the East Sea.
Experts say the latest launch is a "military demonstration" aimed at drawing the attention of the international community ahead of Chinese President Xi Jinping's upcoming visit to South Korea this Thursday.
The South Korean military has heightened its vigilance and beefed up its military readiness against any additional provocations by Pyongyang.
Hwang Sung-hee, Arirang News.