Reports that a Canadian was involved in the deadly shopping mall siege in Kenya have reignited fears about militant groups鈥 recruitment efforts in Canada and the West.

Although the federal government said Monday it has 鈥渁bsolutely no information鈥 to confirm claims that a Canadian was among the militants who stormed an upscale mall in Nairobi over the weekend, killing at least 72 people, there are long-standing concerns about Canadian residents taking part in insurgencies and civil wars abroad.

The issue has been flagged 鈥渆xtensively鈥 by North American security intelligence agencies, said Christian Leuprecht, associate professor of political science at the Royal Military College of Canada and Queen鈥檚 University in Kingston, Ont.

In February, then-head of the Canadian Security Intelligence Service, Richard Fadden, told the Senate Committee on National Security and Defence that CSIS is aware of 鈥渄ozens鈥 of Canadians who have travelled or attempted to travel overseas to engage in terrorism-related activities.

Al-Shabaab, the Somali terrorist group with ties to al Qaeda that claimed responsibility for the Nairobi mall attack, has been able to attract Canadians in recent years.

There are nine known cases of people from Canada travelling overseas or attempting to leave the country to join the group, documented by news organizations and other open sources, Leuprecht said in an interview with CTVNews.ca. The actual number is probably much higher, he said.

Among them is Mohamed Hersi, who was arrested in 2011 at Toronto鈥檚 Pearson International Airport. Police allege he was planning to travel to Somalia via London and Cairo to join al-Shabaab. Hersi鈥檚 lawyer has denied the charges and the case is still before the courts.

Two of the men who simply disappeared from the country turned up dead while fighting for al-Shabaab abroad, Leuprecht said.

鈥淩elative to the size of the Somali community (in Canada), these are very isolated cases,鈥 he said, adding that the problem should not be 鈥渙ver-sensationalized.鈥 

The presumed al-Shabaab recruits also disappeared at different times, which is not suggestive of some kind of an organized network in Canada, Leuprecht said.

By contrast, al-Shabaab鈥檚 aggressive recruiting of young Somali-Americans in Minnesota, for example, has been well-documented.  

鈥淭he more likely risk is that individuals, for the lack of a better word, self-radicalize,鈥 Leuprecht said, noting that al-Shabaab members use social media, including YouTube and Twitter, to reach an audience in the West.

鈥楩oreign fighters鈥 widespread

Leuprecht said it鈥檚 important to note that people join terrorist organizations 鈥渇or all sorts of reasons that may not necessarily be related to ideological, radical leanings.

鈥淟et鈥檚 make sure that we don鈥檛 necessarily just finger the Somali community,鈥 he said. 鈥淚t鈥檚 entirely conceivable that anybody might go and join up鈥t doesn鈥檛 necessarily need to come from the diaspora.鈥

The 鈥渇oreign fighter鈥 problem has a long history in Canada and much of the western world, Leuprecht noted. For example, one recent report flagged 600 Europeans who are known to be fighting alongside the rebels in Syria.

Over the years, various groups have found financial support and recruits in Canada, including the Irish Republican Army and the Tamil Tigers, Leuprecht said.

鈥淚n Canada, it dates back as far as, you could argue, to the Spanish Civil War, with people leaving the country to get engaged in fights of which the government doesn鈥檛 approve,鈥 he said.

Still, Fadden鈥檚 comments to the Senate earlier this year and public reports from CSIS indicate that the intelligence service is 鈥渄eeply concerned鈥 about Canadians鈥 involvements in foreign conflicts, Leuprecht said.

Anyone who joins terrorist groups overseas is likely to harm others and 鈥渂ring disrepute to Canada,鈥 he said. Those individuals may also return one day, bring back radical ideas, begin recruiting others and possibly carry out attacks in Canada, he said.

But Leuprecht said Canadian authorities are doing a good job of preventing potentially radicalized people from leaving the country to join groups like al-Shabaab, 鈥渂ecause there鈥檚 so few of them who actually do.鈥

Michel Juneau-Katsuya, a former CSIS agent, told CTV鈥檚 Canada AM Tuesday that although al-Shabaab only operates in Africa, recruitment and terror financing in other parts of the world is a real concern.

鈥淎l-Shabaab is probably one of the most violent vicious terrorist groups that we currently have on the radar,鈥 he said. 

Juneau-Katsuya said radicalization is 鈥渁 big problem鈥 in Canada. He pointed to the case of two young men from London, Ont. who allegedly took part in a deadly gas plant attack in Algeria early this year. Their high-school friend was jailed in Mauritania over his alleged ties to al Qaeda and he recently returned to Canada.

鈥淲e鈥檙e about to give ourselves a reputation for exporting terrorists very soon,鈥 Juneau-Katsuya said. 鈥淲e鈥檝e got to wake up, understand what radicalism is about, try to understand the early sign of extremism, which is not only confined to a single community or single religion.鈥