Japanese media is reporting the Democratic People's Republic of Korea has grasped the key technology needed to produce a miniature nuclear warhead. It says the warheads can be used in conjunction with its Intermediate Ballistic Missile "Rodong".

Officials from the Japanese Defense Ministry said the DPRK's nuclear technology has made major improvements since their first test in 2006.

Japan and the US are reportedly to discuss the DPRK issue at the upcoming Japan-US summit in Washington. The two countries may join together to punish the DPRK by measures including stopping the international cash flow to the DPRK.