Kim Jong-un has reportedly been studying dated Google Earth photos as he continues to develop his nuclear programme.

The North Korean leader is understood to have hosted a massive celebration to congratulate his nuclear scientists and technicians who steered the country's sixth and largest nuclear test a week ago.

But new propaganda photos released by the regime appear to show him studying maps of the Anderson Air Base in Guam that were taken at least six years ago, amid claims he does not have the technology to precisely pinpoint targets.

Nick Henson at Stanford University's Center for International Security and Cooperation, told Voice of America the evidence suggests that North Korea has no satellites of its own and therefore has to use publicly available images.

It comes as tensions continue to escalate between the country and the US.

The United Nations Security Council unanimously passed its toughest-ever sanctions package against North Korea on Monday.

Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Show all 6 1 /6 Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb Photos released by North Korea show Kim Jong-un talking to subordinates next to a device thought to be the new thermonuclear weapon. There is no way of independently verifying the pictures STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korea claims it has successfully tested an advanced hydrogen bomb which could be loaded onto an intercontinental ballistic missile AFP/Getty Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A diagram on the wall behind Mr Kim shows a bomb mounted inside a cone STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb North Korean leader Kim Jong-Un (C) attending a photo session with participants of the fourth conference of active secretaries of primary organisations of the youth league of the Korean People's Army (KPA) in Pyongyang STR/AFP/Getty Images Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters Kim Jong-un inspects weapon North Korea says is powerful hydrogen bomb A new stamp issued in commemoration of the successful second test launch of the "Hwasong-14" intercontinental ballistic missile KCNA via Reuters

The council imposed a US-drafted ban on the country’s textile exports as well as capping imports of crude oil – but was forced to water down an initial tougher bill which called for a total oil ban for the state.

In response, North Korea's envoy to the UN warned “forthcoming measures” will “make the US suffer the greatest pain” it has ever experienced.

Pyongyang's ambassador, Han Tae Song, made the vitriolic comments at the UN-sponsored Conference on Disarmament in Geneva.

He said: “The Washington regime fired up for political, economic, and military confrontation, [is] obsessed with the wild game of reversing the DPRK's development of nuclear force which has already reached the completion phase”.