The official North Korean news agency said today the communist country's leader Kim Jong-un met his nuclear scientists for a briefing and declared he was greatly pleased that warheads had been miniaturised for use on ballistic missiles.
In a report dated today, the KCNA news agency said Kim told the nuclear researchers that the stronger the country's nuclear strike capability, the more effective it will be as a deterrent to aggression.
Pyongyang has previously claimed it has nuclear warheads small enough to put on long-range missiles, but experts have questioned such claims.