Rocket launch at North Korea's Sohae site (file)
Rocket launch at North Korea's Sohae site (file) Reuters

The nuclear-armed rogue dictator state of North Korea has significantly upgraded its main rocket launch site, according to new satellite imagery revealed by a US research institute in a report on Friday.

The US-Korea Institute at Johns Hopkins School of Advanced International Studies showed how the Sohae launch site on North Korea's western coast was expanded late last year so that it can launch larger rockets - and potentially intercontinental ballistic missiles (ICBMs) capable of carrying a nuclear warhead.

Commercial satellite imagery since then reveals the regime has been working to add a support building and apparently a movable platform, which would enable a rocket to be transferred on rails to the launch pad.

"The Sohae facility upgrade program represents a significant investment of financial, material and personnel resources and is another indicator, along with its public statements, that North Korea is determined to pursue its space program," read the analysis of the institute received by the Associated Press.

UN Security Council resolutions ban North Korea from launching rockets, given that the same "peaceful" space program technology is used to fire cataclysmic ballistic missiles.

The Asian dictatorship has nevertheless continued its rocket development, successfully launching for the first time a submarine-launched ballistic missile (SLBM) capable of carrying a nuclear warhead from underwater earlier this month. That missile joins a mobile ballistic nuclear missile unit it recently added to its arsenal.

Chinese experts warned the US last month that American estimates are wrong and North Korea actually has 20 nuclear weapons, with that arsenal to double next year thanks to the regime's higher than anticipated advanced enrichment capabilities.

North Korea has also been sharing its technology with Iran, and a report on Thursday maintained that a delegation of North Korean nuclear experts visited Iranian nuclear installations in April - after the framework agreement limiting Iranian nuclear activity had already been presented by Western powers negotiating with Tehran.

It was reported last month that US President Barack Obama hid intel from the UN about North Korea transferring rocket components needed to create a nuclear missile to Iran even during the nuclear talks, to try and prevent the UN from acting on the information with increased sanctions.