It was called the South Atlantic Flash.

It remains one of the most enduring mysteries of the Cold War and was believed to have been intended as a message.

Early on Sept. 22, 1979, a dual burst of light was picked up over an empty patch of ocean by a U.S. satellite, an event many intelligence agencies believed was a demonstration of Israeli and possibly South African nuclear capability.

Nobody ever owned up to it.

While South Africa eventually dismantled its nuclear bombs, Israel's program has been an open secret since the mid-1980s with officials pointedly, even today, never confirming or denying its existence.

Both countries were understated, even shrewd about displaying nuclear ambitions.

There is no such subtlety with North Korea.

It almost gleefully advertised the claim it had detonated a hydrogen bomb.

'More gift packages'

On Tuesday, one of North Korea's top diplomats told a United Nations conference in Geneva his country was ready to send "more gift packages" to the United States.

What Han Tae Song meant, precisely, is unclear.

He dismissed the international uproar, including criticism from Israel, over the nuclear test.

Seismic monitors confirm some kind of large explosion took place last weekend at North Korea's test range, but international experts choose their words carefully and filter the precise details of their analysis through the lens of North Korea's official statements.

Unarmed test possible

Defence specialists say, at the moment, Pyongyang is all about showing what it can do and fears of nuclear-tipped missiles raining down on a U.S. or even Canadian city remain a remote possibility.

This picture taken released by North Korea's official Korean Central News Agency shows the successful test-fire of the intercontinental ballistic missile Hwasong-14. There is concern the country will demonstrate it can hit North America by dropping an unarmed missile on an empty patch of ocean or ground. (STR/AFP/Getty Images)

Within the Canadian military establishment, the fear is the regime of Kim Jong-un will "hurl a hunk of metal across the Pacific."

That, according to two defence analysts, is a loose way of saying there is concern the rogue state will want to demonstrate it can hit North America by dropping an unarmed missile on some empty patch of ocean or ground, possibly in the Arctic.

"They want to unambiguously be able to say they can do it," said Danny Lam, an analyst in environmental engineering and defence issues who has studied North Korean military capability.

He said "landing a hunk of metal in Hudson's Bay, for example, would prove the point."

Sending a message

Retired colonel George Petrolekas took the notion a step further.

He said the world should not be surprised to see, sometime in the near future, a small segment of the North Pacific suddenly declared a "no-go area" and that Pyongyang would fire a missile into the sea and detonate a hydrogen bomb in order to prove what they can do.

Jake Sullivan, former national security adviser to Vice President Joe Biden, joins Rosemary Barton to discuss 8:33

"And at some point the North Koreans will demonstrate that they have that capability," said Petrolekas, who advised two of Canada's chiefs of the defence staff during the war in Afghanistan.

The entire provocative show is meant to send a message to the U.S. and its allies: Don't even think about trying to invade us.

"The question has always been: Can they deliver it? I would not be surprised at some point in the next two years that get exposed to a demonstration that it can be delivered."

30 km from Guam

That scenario has some supporting evidence.

As Washington and Pyongyang traded threats over Guam in early August, the official newspaper of the Central Committee of the Workers' Party of Korea printed a statement from the commander of the country's strategic rocket forces.

On Aug. 11, Rodong Sinmun made reference to a plan to fire Hwasong-12 rockets that would "cross the sky above Shimane, Hiroshima and Kochi Prefectures of Japan" and "hit the waters 30 to 40 [km] away from Guam."

Nations across the globe have called for tighter sanctions, but Russian President Vladimir Putin said Tuesday he doesn't believe an even tighter regime would work.

He called for diplomacy.

Russian President Vladimir Putin speaks during his news conference in Xiamen, Fujian province, China, on Tuesday. Putin called for talks with North Korea, warning against "military hysteria." (Mikhail Klimentyev/Associated Press)

The Canadian conundrum

Canada, aside from having few military forces in the region, has little in the way of diplomatic pull, said Petrolekas.

China is the country with the most sway over North Korea and the Trudeau government is not in the position where it can be too forceful with Beijing, he said. The Chinese government does not respond well to lecturing, and there is the Canadian conundrum.

"How do you put pressure on China with without hurting yourself economically?" said Petrolekas. "I don't think we know what we want to do other than announcing with the world that it has got to stop."