The ballistic missile launched by North Korea on Sunday, dubbed the Pukguksong-2, is a new form of high-thrust solid fuel-powered intermediate-range ballistic missile that Pyongyang claims can carry a nuclear warhead.
It is modelled after a submarine-launched ballistic missile which was tested last August.
This is seen as a step up in the isolated state's nuclear capabilities, as it strives towards its stated ambition of creating an intercontinental ballistic missile that can strike the United States.
To date, most of the North's ballistic missiles have relied on liquid fuel. The New York Times cited military analysts as saying in a report yesterday that the use of solid fuel greatly reduces the time required to prepare the missile for launch and increases its mobility on the road, thereby making it more difficult to detect signs of an imminent attack.
The missile was launched on Sunday, reaching a height of 550,000m and range of 500km before landing in the Sea of Japan, also known as the East Sea, without entering Japan waters.
Before details of the new missile came to light, Seoul at first said the missile was likely a modified medium-range Rodong. It then said it was a modified intermediate-range Musudan.
Pyongyang said yesterday it deliberately launched the Pukguksong-2 at a sharp angle to keep it from landing too close to Japan.
Correction note: In an earlier version of the story, we said that the missile landed in the Sea of Japan. The Sea of Japan is referred to as the East Sea by the Koreans.