North Korea expanding nuclear threat and has built 6,000-strong cyber-army, claims South Korea

Missiles could potentially reach the US mainland, South Korea says

South Korea’s defence ministry say that the North has evolved its nuclear and missiles threats, and built a 6,000-strong cyber-army.

According to a white paper released by the ministry and assessed by Yonhap news agency, North Korea appears to have achieved "a significant level" of technology, miniaturising nuclear warheads to fit on ballistic missiles.

These missiles could potentially reach the US mainland, South Korea's defense ministry claimed.

The report also said that North Korea has a 6,000-strong "cyber-army", dedicated to disrupting the South's military and government.

This figure is a doubling of its earlier estimate that the North had a cyberwarfare staff of 3,000.

The paper carried a technological analysis of the North's nuclear program, the first analysis of its kind.

The paper said: "North Korea's capabilities of miniaturizing nuclear weapons appear to have reached a significant level.

"North Korea is presumed to have secured some 40 kilograms of weapons-grade plutonium by reprocessing spent nuclear fuel roads multiple times, and it is evaluated to have been working on the highly enriched uranium program."

The ministry highlights North Korea's evolving nuclear and missiles threats, after Pyongyang’s third nuclear test in February 2013, even though the North is yet to demonstrate its new capabilities.

An unnamed ministry official told Yonhap: "We don't have any intelligence that North Korea completed the miniaturisation.

“In consideration of the fact that acquiring such technology takes around two to seven years in general and eight years have passed since the North conducted its first nuclear test, however, its capability for small nuclear warheads would have reached a significant level."

The paper follows previous reports from South Korea’s defence ministry which outlined the North's two underground detonation tests.