"We should be mindful that just last month Japanese officials intercepted some North Koreans who were trying to smuggle a magnetometer to Myanmar," Chamberlin told Al Jazeera.

He noted that the dual-use technology for measuring magnetic fields could be used for archaeology but also in guidance systems for ballistic missiles.

Common ground

Myanmar and North Korea are among the world's most isolated nations and on the face of it the two would appear to share much common ground.

"The past track record of North Korea... means the international community and the US have good grounds to be concerned"

John Swenson-Wright, Seoul National University

Both are effectively run as military dictatorships and are faced with a raft of international sanctions.

Both are also headed by highly-secretive governments and leaders, who shun almost all outside contact and keep a tight rein on information within their societies.

There would also appear to be a strong foundation for a mutually beneficial trading relationship between the two nations.

North Korea has a massive armaments industry and is in desperate need of resources to prop up its economy; while Myanmar, for its part, has a large military in need of new weapons as well as substantial reserves of oil, gas and other natural resources.

But relations between Myanmar and North Korea have not always been close.

In 1983 Myanmar, then known as Burma, cut off diplomatic relations following a North Korean bomb attack in Yangon.

The blast at the city's Martyr's Mausoleum killed more than a dozen visiting South Koreans including several senior government officials.

It later emerged that the bomb had been planted by North Korean agents acting on the orders of Kim Jong-il – now North Korea's supreme leader.

The bombing effectively froze all contact between the two countries for years, with formal relations not restored until 2007.

Barter deals

"We have to be very careful that the drift doesn't go off track into something that is speculative and is not necessarily a current and present danger."

Richard Broinowski, former Australian diplomat

Beginning with a series of barter deals involving the transfer of North Korean-made small arms to Myanmar, observers have noted a rapidly growing and apparently increasingly close relationship between the two countries.

Given North Korea's history, that alone should be cause for alarm, John Swenson-Wright, a Korea Specialist with Seoul National University, told Al Jazeera.

"The past track record of North Korea in terms of proliferation means the international community and the US have good grounds to be concerned about what North Korea may be doing," he said.

Since Myanmar and North Korea restored diplomatic ties observers say there have been a number of high-level exchanges of officials, and recent reports have indicated an increasingly close military relationship.

Last month a North Korean ship, the Kang Nam 1, was tracked by the US navy as it left port near Pyongyang apparently headed for Myanmar.

Although the vessel later turned about and returned to North Korea before reaching is destination, several reports quoting intelligence sources said the ship was suspected to be carrying missiles and missile parts.

Secret tunnels

North Korea is believed to have helped the contruction of a secret tunnel network [DVB]
Also in June the Democratic Voice of Burma (DVB), a Norwegian-based TV network run by Myanmar exiles, released photos and video it said showed a secret network of tunnels being built by North Korean engineers for the Myanmar military.

The tunnels, large enough to drive trucks through, are believed to be part of new national defence network, the DVB said.

It said the tunnels included facilities for housing command and control centres, as well as advanced missiles.

Writing earlier this month in the Wall Street Journal, Aung Zaw, a Myanmar exile and editor of Thailand-based Irrawaddy magazine, said Myanmar's military rulers had a "burning ambition" to acquire modern missile technology – and that North Korea was the natural partner.

But will this growing relationship include a nuclear element?

Richard Broinowski, a former Australian diplomat who was based in both Myanmar and South Korea, said the likelihood that North Korea was supplying weapons to Myanmar was neither particularly surprising nor novel.

"Myanmar has been getting its small arms from somewhere for a long time," he told Al Jazeera.

But he said speculation over nuclear cooperation was "a bit of a stretch", noting that North Korea's own ability to actually produce a working nuclear weapon that would fit on a missile or a warplane was still some way down the track.

As for Myanmar itself, Broinowski, who has also written widely about nuclear proliferation, said the country had "a long way to go if they are going to get any sort of technical capacity to make a nuclear weapon – let alone a weapon that could be deliverable."

"We have to be very careful that the drift doesn't go off track into something that is speculative and is not necessarily a current and present danger."