Officials are trying to reassure the public that Montreal's Trudeau airport is secure and there are strict screening procedures in place to vet employees, following a report about potentially radicalized workers.

"We do conduct, on a continuous basis, threat analysis, risk analysis, vulnerability analysis, just to make sure we can face any kind of threat," said Pierre-Paul Pharand, vice-president of airport operations.

The comments come following an investigation by the French-language television station TVA that revealed four airport employees had their security clearance revoked as a precautionary measure due to concerns they were becoming radicalized.

According to the report, at least one had access to runways and had been the subject of a police investigation.

One suggested committing an attack similar to the one in Paris in 2015 that killed 130 people, while another shared ISIS propaganda on his Facebook page.

Two of the four employees still work at the airport, according to TVA.

Pharand confirmed the people mentioned in the report had their security badges withdrawn and are not allowed in restricted areas.

Prime Minister Justin Trudeau said the government will cut no corners when it comes to ensuring air travel safety.

"When issues come to light, we deal with them in a responsible way. We look into what is happening and how to ensure that Canadians remain safe," he said.

Continuous vetting process

Pharand said the four employees in question don't work for Aéroports de Montréal, the corporation that runs the airport, therefore the airport isn't able to terminate their employment. He said he doesn't know who they are or who they work for.

Prospective employees are vetted before they start working at the airport, he explained, but there are other processes that kick in once they're hired, including surveillance, to ensure the airport is safe.

The Airport Patrol, Montreal police, RCMP, Canadian Border Services Agency, Canadian Security Intelligence Service and Sûreté du Québec all have jurisdiction at the airport. (Radio-Canada)

A number of law enforcement agencies have jurisdiction at the airport, including the Airport Patrol, Montreal police, RCMP, Canadian Border Services Agency, Canadian Security Intelligence Service and Sûreté du Québec.

Pharand said he has no information about an imminent threat toward the airport.

Public Security Minister Martin Coiteux said he is watching the "serious situation" closely and has been in touch with federal Transport Minister Marc Garneau, since his department oversees air transportation.

Montreal Mayor Denis Coderre said he is willing to work with Transport Canada and airport officials. He said more municipal police officers could be allotted to the airport if necessary.

"It's a matter of ongoing vigilance, but I think there's no [need] to panic," he said.

Tyler Stoute, who works at a duty-free shop in international departures, said he's concerned by the level of security.

"It is a bit concerning, because there are many people who just walk through security every day without being searched and that is definitely a concern," he said.

As an employee, Stoute has a card that allows him to get special clearance, though he can still be subject to random security checks. New employees on temporary passes are, like passengers, required to go through security any time they go into restricted areas.

Airport security multi-layered, Ottawa says

In an emailed statement, Garneau said the country's airports are "secure environments protected by a multi-layered approach to security."

"Canadians can be assured that their 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 said.

Garneau explained that in order to enter the restricted area of an airport, employees must obtain a transportation security clearance (TSC) from Transport Canada.

Garneau says when criminal activity is identified, 'immediate action' is taken. (Sean Kilpatrick/Canadian Press)

That process includes background checks with CSIS, the RCMP and Immigration, Refugees and Citizenship Canada.

All TSC holders are verified daily in a police database. When criminal activity is identified, "immediate action" is taken, which can include the suspension or revocation of the clearance, Garneau said.

More than 1,100 clearances have been refused or cancelled at airports across the country over the past two years.

Conservative public security critic Tony Clement issued a statement saying the TVA report was "troubling," adding the Liberals must "take all measures necessary to ensure security levels are being maintained."