`North Korea leader wants nuke deterrent as proof against downfall`

Athens: North Korea's leader Kim Jong-Un is afraid of sharing the fate of slain dictators Saddam Hussein, Moamer Kadhafi and Al-Qaeda's Osama bin Laden, and is working on a nuclear deterrent for this purpose, a former Japanese defence minister said on Friday.

"Kim is very afraid to be killed like (Iraq's) Saddam Hussein, (Libya's) Moamer Kadhafi or Osama bin Laden," Satoshi Morimoto, who is now a national security expert, told a conference in Athens.

"So as long as they maintain nuclear capability they think they can survive," said Morimoto, a professor at Tokyo's Takushoku University who served as defence minister in 2012.

North Korea says it tested a miniaturised hydrogen bomb on January 6 -- a claim largely dismissed by experts who argue the yield was far too low for a full-fledged thermonuclear device.

Morimoto argued that given available data, the weapon tested was likely a "small bomb with a launch missile."

He recalled a similar situation in 1953, when the Soviet Union said it had tested a hydrogen bomb, but the United States considered it a smaller-scale thermonuclear weapon.

Moscow's first 'true' hydrogen bomb test came two years later.

North Korea "is in the process of developing a hydrogen bomb, but not yet," Morimoto said.

"Despite sanctions, they never gave up nuclear development and ballistic missiles," he said.