MONTREAL: If the news that two Canadians were among the hostage takers who triggered the bloody siege of an Algerian gas plant was a surprise to many, perhaps it shouldn't have been.
While there has never been an attack on Canada's soil, experts say that since the 1990s the country has unwittingly become a base of operation for Islamist militants, particularly Algerians.
The attack on the In Amenas plant, mounted by Mokhtar Belmokhtar's Al-Qaeda linked "Signatories in Blood", left 37 foreign workers dead and raised worrying questions about the reach and capabilities of North African militants.
Observers in Canada say their country hosts extremist cells of its own.
"Particularly in Montreal, there's a large Algerian network that has operated here for some 20 years," Michel Juneau-Katsuya, a former senior agent with the Canadian Security Intelligence Service told AFP.
The city has a large North African diaspora and many historical links to militants across the Atlantic.
"Some in Canada still harbor extremist convictions or close to that of the Armed Islamic Group," former French anti-terrorism judge Jean-Louis Bruguiere noted in a September 2011 interview with the daily La Presse.
"With the rise of Al-Qaeda in the Islamic Maghreb, we should be worried."
The Armed Islamic Group is blamed for more than a thousand deaths in attacks in Algeria and in France in the 1990s, and some of its members immigrated to Canada during that period.
"They landed as refugees, claiming to be fleeing the civil war," explains Fabrice de Pierrebourg, an investigative reporter for La Presse.
The Algerians set up a cell, which became known as "The Montreal Cell." It was finally dismantled in 1999.
Five of the cell members were sentenced in France in 2001 for ties to the Gang de Roubaix, which was blamed for bank attacks, murder and a failed car bomb attack against a G7 finance ministers meeting in France.
The Montreal Cell's best-known member Ahmed Ressam -- also known as the "Millennium Bomber" -- was arrested on the Canada-US border in 1999 driving a car packed with explosives.
He was jailed for plotting to bomb the Los Angeles International Airport.
Of greater notoriety is Toronto-born Omar Khadr, now the youngest detainee ever held at the US "war on terror" prison at Guantanamo Bay, Cuba, jailed for killing a US soldier in Afghanistan.
His Egyptian-born father was considered an influential member of Al-Qaeda before he was killed in Pakistan in 2003 and his clan has been dubbed Canada's "First family of Terror."
The family moved from Canada to the Pakistan-Afghanistan border area in 1990 to help with reconstruction after the withdrawal of Soviet forces, according to an online family biography.
They then lived in a compound in Jalalabad, Afghanistan, and allegedly met Osama bin Laden.
The US military and the Canadian government say the young Khadr reported to an Al-Qaeda training camp in 2001 to learn how to make bombs.
In pre-trial hearings, prosecutors showed video of him, sitting cross-legged on the ground and smiling as he fashioned explosive devices.
According to Juneau-Katsuya these plots and attacks, like the more recent one at the Algerian gas plant, are reminders "that Canada has allowed recruiting and fundraising" by extremists.
"Canada has always been more of a base of operation than a target," he added, suggesting that this might explain why there has never been an attack in Canada by Islamic militants.
Since the September 11, 2001 attacks in the United States, however, there have been attempts -- notably the plot by the so-called "Toronto 18" to storm Canada's parliament and decapitate the prime minister.
The homegrown Islamist militants were arrested in a police sting operation in 2006, but none had any direct links to Al Qaeda and others charged with terrorism-related offenses have mostly been loners, said de Pierrebourg.
Generally, they turn out to be dual nationals -- immigrants or descendants of recent immigrants -- taking advantage of the ease of traveling on a Canadian passport to reach battlegrounds from Afghanistan to Somalia, say experts.
Canadian Foreign Affairs Minister John Baird said Ottawa is investigating claims that Canadian nationals were involved in the Algeria hostage siege.
"Canada condemns in the strongest possible terms this deplorable and cowardly act and all terrorist groups which seek to create and perpetuate insecurity," he added through a spokesman.
Meanwhile, Canada's spy service has warned the Canadian government about an upward trend in domestic Islamist extremism, according to a report obtained by the Canadian Broadcasting Corporation.
"Small groups (of) Canadians will continue to be inspired by the narrative and seek to engage in extremist activities both at home and abroad," reads the threat assessment obtained by the public broadcaster.