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