Dockworkers and foreign businessmen have seen evidence of alleged secret nuclear and missiles weapons sites being built deep in the Myanmar jungle, a leaked US diplomatic cable said.
"The North Koreans, aided by Burmese workers, are constructing a concrete-reinforced underground facility that is '500ft from the top of the cave to the top of the hill above'," according to the cable, published by the British daily The Guardian.
The cable from the US embassy in Rangoon was among those released yesterday by the anti-secrecy website WikiLeaks, and quoted a Myanmar officer who said he had witnessed the North Korean technicians helping the construction work.
One foreign businessman told the embassy that he had seen reinforced steel bar, larger than for just a factory project, being shipped on a barge. While dockworkers also told of seeing suspicious cargo.
A cable dating from August 2004 revealed information from a Myanmar officer in an engineering unit who said surface-to-air missiles were being built at a site in a town called Minbu in west-central Myanmar.
He said some 300 North Koreans were working at the site, although the US cable noted this was improbably high, The Guardian said.
The military junta in Myanmar has dismissed reports of its nuclear intentions and brushed aside Western concerns about possible cooperation with North Korea.
But in July US Secretary of State Hillary Clinton expressed worries about military ties between the two countries saying a ship from Pyongyang had recently delivered military equipment to Myanmar, formerly known as Burma.
"We continue to be concerned by the reports that Burma may be seeking assistance from North Korea with regard to a nuclear program," she said.
A June documentary by the Norwegian-based news group Democratic Voice of Burma (DVB) said Myanmar was trying to develop nuclear weapons, citing a senior army defector and years of "top secret material."
The DVB documentary gathered thousands of photos and defector testimony, some regarding Myanmar's network of secret underground bunkers and tunnels, which were allegedly built with the help of North Korean expertise.
According to another leaked US cable from 2009, a well-placed source in the Myanmar military government said General Thura Shwe Mann had visited North Korea in 2008.
But the source backtracked later insisting the talks were only exploratory.