Flags of North Korea and Iran
Flags of North Korea and IraniStock

North Korea’s sudden advancement in developing nuclear weapons may be due to secret support from Iran, the British Sunday Telegraph reports.

According to the report, the British Foreign Office is investigating whether “current and former nuclear states” helped North Korean leader Kim Jong-Un in his drive to mount nuclear warheads on missiles.

Senior sources told The Sunday Telegraph it is not credible that North Korean scientists alone brought about the technological advances.

Iran is top of the list of countries suspected of giving some form of assistance, while Russia is also in the spotlight, according to the British newspaper.

The fear is that outside influences have provided North Korea with equipment or expertise that has moved them closer to becoming a nuclear nation.

“North Korean scientists are people of some ability, but clearly they’re not doing it entirely in a vacuum,” said one Government minister who was not named.

Another Foreign Office source told the newspaper, “For them to have done this entirely on their own stretches the bounds of credulity.”

North Korea, which has already carried out numerous ballistic missile and nuclear tests, took things further last week with a successful hydrogen bomb test, its most powerful nuclear test to date.

The test followed a threat by Pyongyang, a tiny U.S. territory in the Pacific. The threat came in response to U.S. President Donald Trump’s warning that Pyongyang faced "fire and fury like the world has never seen" if it continued to threaten the United States with its missile and nuclear programs.

This week, North Korea warned it would send “more gift packages” to the U.S. should it continue to pressure Pyongyang.

According to The Telegraph, Britain’s hope is that identifying any link to another country helping North Korea could open new diplomatic avenues for exerting pressure on the regime, which has refused to change course despite economic sanctions.

British Foreign Secretary Boris Johnson hinted at his department’s concerns last week as he took questions from MPs about the crisis.

“There is currently an investigation into exactly how the country has managed to make this leap in technological ability,” Johnson said.

“We are looking at the possible role that may have been played, inadvertently or otherwise, by some current and former nuclear states,” Johnson added, though he declined to name who he had in mind.

The British report further noted that at the start of the year it was estimated that North Korea would need a decade before they could launch intercontinental ballistic missile with nuclear warheads. That has now been slashed to just a few years, according to sources.

Britain’s most senior Cabinet ministers were briefed on the “fast forward” in the country’s nuclear capabilities at a National Security Council meeting last week, attended by senior intelligence figures.

Prime Minister Theresa May also talked to Trump about North Korea just days after he said “all options” remained on the table.

The pair agreed to use “all the leverage they had” to stop Kim from developing nuclear weapons and “agreed on the key role China has to play,” said an official briefing following the conversation.

In the wake of North Korea’s latest test, the United States submitted a draft resolution to the UN Security Council in which it demands an oil embargo on North Korea and a freeze on the foreign assets of Kim.

The resolution would go far beyond seven previous rounds of sanctions and would rock Kim's isolated regime.