North Korea army test-fired KN-02 surface-to-surface ballistic missile into the Sea of Japan 1603131.

The authorities have yet to confirm the exact time of the launching. North Korea has been holding its own military exercise in the Sea of Japan and the firing of the two missiles into open waters is believed to be a part of an exercise designed to gauge their accuracy.

The North Korean KN-02 short-range ballistic missile is an upgraded vesion of the Russian-made Tochka (SS-21 Scarab). This type of missile can be used for precision strikes against important targets, such as airfields, command posts, bridges, storage facilities and troops concentrations.

The DPRK's launch came after Washington and Seoul began their " Key Resolve" joint military exercises on Monday despite Pyongyang' s warning of annulment of the armistice agreement that halted the 1950-53 Korean War.

At the same time, United States announced the deployment of 14 additional ground-based interceptor missiles in Alaska by 2017, a move which apparently reflects that Washington is taking North Korea's long-range missile threats more seriously.

The Pentagon also plans to set up a new radar station in Japan to beef up its capability to detect any missile fired from North Korea.