The federal government is moving quickly to deport an alleged spy arrested in Montreal on a rarely used national security certificate.
The man was taken into custody by the Canada Border Services Agency on Tuesday.
Court documents made public Thursday say he is a foreign national operating under the alias Paul William Hampel.
The papers accuse him of engaging "in an act of espionage or an act of subversion" and posing "a danger to the security of Canada."
They shed no light on speculation the man was a Russian spy out to pilfer Canadian secrets.
Melisa Leclerc, a spokeswoman for Public Safety Minister Stockwell Day, said more information will become available as the legal process unfolds in the Federal Court of Canada.
It was unclear whether hearings would take place in Montreal or Ottawa, or when the man might appear in court.
"There's not much I can say, because it's before the court," Ms. Leclerc said.
It is the first time in a decade that a security certificate has been filed in an espionage case. In 1996, two Russian spies were deported from Canada in disgrace.
Under federal immigration law, the government may use a certificate to deport a non-citizen suspected of being a risk to Canadian security. The certificate must be signed by the ministers of immigration and public safety.
A federal judge examines the case, either upholding the certificate as reasonable or quashing it and setting the suspect free. The individual receives a summary of the case, stripped of information the judge believes could harm national security if made public.
The person named in the certificate is also given a chance to provide evidence and be heard in open court.
Critics argue the certificate system is unconstitutional because the person named does not have full access to the evidence against him. The Supreme Court of Canada is about to rule on a challenge to the certificate regime.
The certificate system has become a flashpoint in Canada's fight against terrorism, drawing criticism from human rights activists, lawyers and scholars.
The certificates have now been used in 28 cases, almost all involving terrorism or espionage, since 1991.
It is well known that foreign countries send agents to Canada in pursuit of economic and military secrets.
Dmitriy Olshevsky and Yelena Olshevskaya, who went by the bogus names Ian and Laurie Lambert, made headlines in 1996 when they were arrested and promptly removed from Canada.
Friends and co-workers were stunned to learn the pair were actually "sleeper" agents for the Russian Foreign Intelligence Service, or SVR, the successor to the notorious KGB.
Two Russian diplomats kicked out of Canada in 2002 were military attaches at the Russian Embassy in Ottawa, suspected by many of being involved in espionage.