An accused spy was arrested at a Montreal airport on Tuesday night, the country's first espionage arrest in 10 years.
Canada Border Services agents took the man into custody at Pierre Elliott Trudeau International Airport as he prepared to board a plane out of the country.
"A foreign national alleging to be a Canadian citizen named Paul William Hampel was arrested in Montreal after a [national] security certificate under the Immigration and Refugee Protection Act was issued against him," said Melissa Leclerc, a spokesman for Public Safety Minister Stockwell Day.
The certificate must be signed by two federal cabinet ministers. Day and Immigration Minister Monte Solberg signed the document, which authorized the man's arrest for engaging in espionage, or an act of subversion against a democratic government.
News reports say the man could be from Russia. He reportedly slipped into Canada years ago, and kept a low profile.
A federal court judge will set a hearing date for the man, who is being held in Montreal.
Canada an attractive target
A former director of Canada's spy agency said the arrest likely signifies either that the person was deemed a threat to national security or that the government is sending a signal to foreign countries that Canada is watching and won't put up with espionage.
"I think it does send a signal that we remain vigilant and we remain concerned and we're really not going to have people running around doing things they shouldn't do and abusing the hospitality of this country," said Reid Morden.
Canada is an attractive target because of its advanced industries, including aviation and telecommunications, and its proximity to the United States, he said.
Ottawa expelled two Russian military attachés in 2002 on suspicion of espionage, while two Russian spies were deported in 1996.
Dmitriy Olshevsky and Yelena Olshevskaya, who went by the bogus names Ian and Laurie Lambert, were arrested and swiftly removed from Canada in 1996.
3 men detained under security certificates
The last time a security certificate was issued was in 2003, when the former Liberal government approved the arrest of alleged al-Qaeda member Adil Charkaoui.
He's one of five men arrested under security certificates for suspicion of terrorism. The certificates allow police to hold prisoners without charging them or giving them full access to the evidence against them.
Mahmoud Jaballah, Hassan Almrei and Mohammed Majoub remain detained at the Immigration Holding Centre in Kingston, Ont. Charkaoui and another suspect, Mohamed Harkat, have been released on bail under strict conditions.
Harkat, Charkaoui and Almrei have challenged the legality of the certificates, all the way to the Supreme Court of Canada.
In June, lawyers for the federal government argued that the certificates were necessary because the importance of national security outweighed the rights of suspects who are detained.
A judgment is pending.
With files from the Canadian Press
An alleged Russian spy was arrested in Montreal, having threatened national security. The man is identified as a Russian spy and has been living under a false name. 

As he prepared to board a plane out of Canada, Canada Border Services agents took the man into custody at Pierre Elliott Trudeau International Airport in Montreal on Tuesday. Public Safety Minister Stockwell Day and Immigration Minister Monte Solberg signed the document that authorized the man's arrest. 

This document is called the national security certificate and is rarely used. The certificate alerts Ottawa about possible threats to the country. The ministers of immigration and public safety are obliged to sign the national security certificate.

"The government's most important duty is to ensure the security of all Canadians. A security certificate has been issued ... against a foreign national. He is now in custody in Montreal," said Melissa Leclerc, spokeswoman for Public Safety Minister Stockwell Day. "A foreign national alleging to be a Canadian citizen named Paul William Hampel was arrested in Montreal after a national security certificate under the Immigration and Refugee Protection Act was issued against him."

The man came to Canada several years ago with the name of Paul William Hampel, and is now reported to be false. Officials at the Canadian Security Intelligence Service (CSIS) are working on identifying the man who entered Canada years ago.

"He is now in custody in Montreal. This is not a counter-terrorism case. More information will become available as the Federal Court process unfolds. Any speculation about the individual's other nationality is premature at this point," Barbara Campion, a spokesperson for CSIS.

Ottawa believed the man had been "engaging in an act of espionage or an act of subversion," and "belonged to an organization that there are reasonable grounds to believe engages."

"I don't think we're going to get the most intimate of details, no, not at all," he told CTV Montreal....We'll see a public version of the allegations that will be released by the federal court judge who is going to be responsible for reviewing the basis upon which cabinet will have declared this individual subject to a security certificate. beyond that, though, we may see things settle more quietly between governments," said David Harris, former chief of strategic planning at CSIS.

"There are also influence operations where countries might try to influence their expatriates and émigré communities in Canada. Beyond that, there is a real appetite building among many countries for technological secrets," he said. "They can be of use to industries of the sponsoring nations and these things can have values in the billions for the economies of those countries undertaking these operations."

Reports say the man's methods in Canada matched the techniques used by the Russian intelligence agency's Directorate S, which runs the Russian spy network.

Twenty people since 1991 have been charged under the Security Certificate legislation in Canada. The last time it was used was in 2003.

The court hearing for the man being held in Montreal will be on Wednesday. It is still unclear if the hearing will be in Ottawa, the nations capital, or in Montreal. 

More information will be released as the case progresses.