A new leak suggests that Canada is using some of its embassies abroad for electronic-eavesdropping operations that work in concert with similar U.S. programs.

A U.S. National Security Agency document about a signals intelligence (SigInt) program codenamed "Stateroom" was published this week by Germany's Der Spiegel magazine. The document, a guide to the program, was among material obtained by former NSA contractor Edward Snowden.

"STATEROOM sites are covert SIGINT collection sites located in diplomatic facilities abroad," the leaked document says. "SIGINT agencies hosting such sites include … Communication Security Establishments [sic] or CSE (at Canadian diplomatic facilities)."

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The leaked document does not give the locations of the alleged listening posts. It says that, in general, such surveillance equipment is often concealed "in false architectural features or roof maintenance sheds" atop embassies. "Their true mission is not known by the majority of diplomatic staff at the facility," it adds

A Parliamentarian who on Tuesday introduced a motion to increase scrutiny of federal intelligence agencies said the document shows Canadians do not know enough about the Communications Security Establishment Canada (CSEC).

"We really don't know what they're up to," said Jack Harris, the NDP's long-serving defence critic. "… We're dealing with the secret work of spies and intelligence and whether what is being done is what ought to be done."

Government representatives at CSEC and Foreign Affairs declined to comment directly on the leak. A spokeswoman for Defence Minister Rob Nicholson, who gives CSEC its direction, also declined to comment.

In 1995, former CSEC employee Mike Frost wrote in his memoir, Spyworld, that he set up "listening posts" at Canadian embassies. His book says CSEC signals intelligence technicians during the Cold War were funded and mentored by NSA counterparts who taught them how to conceal a piece of spy machinery inside what appeared to be an office safe.

One 1972 caper recounted in the book involved agents cutting a five-foot satellite dish into 12 wedges and smuggling the equipment into Moscow before reassembling it in the attic of the Canadian embassy there. Reports were then passed back to Canada in diplomatic bags, according to the book. It was a standard courtesy for CSEC to turn off its listening gear in Moscow when important British or U.S. allies visited, according to Spyworld.

Newly leaked material indicates that close partnerships still exist among the so-called "Five Eyes" – the alliance of intelligence agencies from English-speaking countries that agree not to spy on each other while collecting intelligence on just about everybody else.

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The Five Eyes agencies may have teamed up to spy on BlackBerrys belonging to foreign diplomats at a 2009 meeting of the G20 in London, according to a previously published leak from Mr. Snowden, who now lives in Moscow as the United States seeks to arrest him on espionage charges.

According to the Stateroom document, Britain, Canada, the United States and Australia still run interrelated surveillance operations from their embassies. (New Zealand, the fifth "eye," is not mentioned.)

"It's not surprising, but it is certainly significant that it is disclosed," said Wesley Wark, a Canadian professor who specializes in intelligence matters. "… There is still great value in having close access to telecommunications around the world, particularly if you are interested in cellphone communications."

Mr. Wark's point about "close" spying contrasts with a more far-reaching 21st century surveillance methodology highlighted earlier this month.

A leaked 2012 presentation showed that CSEC officers analyzed communications flow around Brazil's energy ministry. This suggests CSEC has access to vast databases of previously logged global telecommunications traffic – giving the agency a very far reach in determining which telephones and computer servers in the world might yield the most intelligence for Canada.

With a report from Campbell Clark in Ottawa