In September, Donald Trump tweeted that long queues for petrol were forming in North Korea as a result of UN Security Council sanctions on the regime’s oil imports over its nuclear test earlier that month.

But according to The Centre for Strategic and International Studies, a Washington DC based think tank, recent satellite imagery has not shown significant changes at six petrol stations in Pyongyang.

In a report written by North Korea experts Joseph Bermudez and Lisa Collins, they said: "All the facilities examined appear to be in a relatively good state of repair and operational.”

One set of photos were taken in April, before speculation China may have been cutting oil supply to its neighbour, and the other in November.

The report added: "While the satellite imagery used in this analysis cannot determine whether the reports of long gas lines in Pyongyang or reports of dramatic fluctuations in gasoline and diesel fuel pricing that allegedly occurred during the July-September period are valid.

“It does indicate that if they did occur they do not appear to have had any long-lasting effects upon either the facilities themselves or the general volume or pattern of vehicle traffic in the city."

It also said there was not a line of vehicles queueing for fuel, although cars could be seen at fuel pumps.

Traffic patterns were “essentially unchanged” in an around the facilities.

There is speculation that Kim Jong-un is funding his regime and flouting the UN sanctions via illegal hacking of the cryptocurrency bitcoin.

A North Korean cyber army of 7,000 hackers around the world has changed tactics over the past two years.

It has been pilfering from banks and, more recently, focusing on cryptocurrencies, according to cybersecurity researchers.

North Korea has denied involvement in the hacking incidents.

Stealing bitcoin could be attractive to North Korea because of the huge increase of the value of the cyber currency in a relatively short period.

One bitcoin was worth under $1,000 at the start of the year and has surged to as high as nearly $20,000 this past weekend.

At least $7million (£5.25million) in virtual currency was stolen in the Bithumb hack in February.

But because of the surge in value of bitcoin and other cryptocurrencies, the amount is now said to be worth more than $82million.

Hackers also stole the personal information of around 30,000 people in the attack.

And they demanded a further $5.5million in exchange for deleting some of the information they had stolen.

Sources in the National Intelligence Service also suspect the North of being behind the hacking of another exchange, Coins, in September, the South Korean news agency Yonhap said.

Kim Jong-un has been ploughing money into his nuclear and ballistic missile programmes despite crippling economic sanctions which have blocked the export of the North’s biggest cash sources.

President Donald Trump said the sanctions had been successful in isolating the hermit kingdom, but warned there was “much more work to do”.

Unveiling his national security strategy in Washington DC, he said: “Our campaign of maximum pressure on the North Korean regime has resulted in the toughest ever sanctions.

“We have united our allies in an unprecedented effort to isolate North Korea however there is much more work to do.

“America and its allies will take all necessary steps to achieve a denuclearisation and ensure that this regime cannot threaten the world."