North Korea shares rare glimpse into secret facility used to produce nuclear materials

North Korea has offered a rare glimpse into a secretive facility to produce weapons-grade uranium as state media reported leader Kim Jong Un visited the area.

Friday’s report (September 13) said Mr Kim called for stronger efforts to 'exponentially' increase the number of his nuclear weapons.

It is unclear if the site is at the North’s main Yongbyon nuclear complex, but it is the North’s first public disclosure of a uranium-enrichment facility since it showed one at Yongbyon to visiting American scholars in 2010.

Kim Jong Un seen inspecting the Nuclear Weapons Institute and the production base of weapons-grade nuclear materials (Kim Jae-Hwan/SOPA Images/LightRocket via Getty Images)

While the latest unveiling is likely an attempt to apply more pressure on the US and its allies, the images North Korea’s media released of the area could provide outsiders with a valuable source of information for estimating the amount of nuclear ingredients that North Korea has produced.

During a visit to the Nuclear Weapons Institute and the production base of weapon-grade nuclear materials, Mr Kim expressed 'great satisfaction repeatedly over the wonderful technical force of the nuclear power field' held by North Korea, the official Korean Central News Agency (KCNA) reported.

KCNA said he went around the control room of the uranium enrichment base and a construction site that would expand its capacity for producing nuclear weapons.

Mr Kim has called for more nuclear bombs to be made at the facility (Kim Jae-Hwan/SOPA Images/LightRocket via Getty Images)

State media photos showed Mr Kim being briefed by scientists while walking along long lines of tall grey tubes, but KCNA did not say when he visited the facilities and where they are located.

KCNA said Mr Kim stressed the need to further augment the number of centrifuges to 'exponentially increase the nuclear weapons for self-defence' - a goal he has repeatedly stated in recent years.

He believes North Korea needs greater defence and pre-emptive attack capabilities because 'anti-(North Korea) nuclear threats perpetrated by the US imperialists-led vassal forces have become more undisguised and crossed the red-line', as per KCNA.

North Korea are concerned by threats from the US and South Korea (Kim Jae-Hwan/SOPA Images/LightRocket via Getty Images)

It said he ordered officials to push forward the introduction of a new-type centrifuge, which has reached its completion stage.

North Korea first showed a uranium enrichment site in Yongbyon to the outside world in November 2010, when it allowed a visiting delegation of Stanford University scholars led by nuclear physicist Siegfried Hecker to tour its centrifuges.

North Korean officials then reportedly told Mr Hecker that 2,000 centrifuges were already installed and running at Yongbyon.

It's thought that anywhere between six to 18 nuclear bombs are built by the country each year.