The Canadian government said on Wednesday that it would take steps to counter any potential threats following a report saying workers at Montreal's airport had been radicalised.
"The security and safety of all Canadians in airports and elsewhere remains a priority for this government. And we'll continue to work with all partners to ensure that our airports remain secure," Prime Minister Justin Trudeau said.
According to the Journal de Montreal newspaper, at least four workers at the Montreal international airport had their security clearances revoked after showing signs of radicalisation.
They reportedly had viewed online propaganda for the Islamic State group and visited websites that describe how to make a bomb.
Opposition Conservative MP Tony Clement called the reports "troubling" and called for an immediate investigation.
He also called for security to be stepped up while reminding of "the need to be ever vigilant against the threat of radical Islamic terrorism."
Transport Minister Marc Garneau assured that the government "takes security matters very seriously and will not hesitate to take appropriate action to mitigate risks and respond to any threats, when identified, to the transportation system."
He added that workers in the transport sector with security clearances are subject to continuous vetting and their access to restricted areas is "verified daily in a police database."
He noted that more than 1,100 Canadian airport workers have been refused or have had their clearance revoked for one reason or another over the past two years.