Thieves have made off with an undisclosed amount of money after an armoured truck robbery in Brossard Thursday night.Police say two armed men--possibly wearing Halloween masks--attacked two employees of the Garda security firm at a Royal Bank branch at Place Portobello around 11 p.m. Thursday.

Longueuil police spokesman Ghislain Vallieres says the thieves attacked guards with pepper spray before making off with an unconfirmed sum of money.

Earlier reports that they took $431,000 have not been confirmed by Garda.

The guards were taken to hospital to be treated for their injuries.Longueuil Police spokesperson Sylvain Stringer told the Canadian Press that police will be reviewing security camera footage to learn more about the incident.

Police are also looking for witnesses to help in the investigation, police spokesperson Ghislain Vallieres told CTV Montreal.

So far, the police haven’t released any descriptions of the suspects or vehicle they were driving. Police say they are also unsure if the men worked alone or had other help.

Police are planning to meet with witnesses and consult security video to discern what happened during the heist, and to determine if the two armed men had any accomplices.

Union wants change

Guy Vaillancourt, VP Garda Armoured Truck Workers Union said that changes are necessary to deter thefts.

“It’s a shame, it should never have happened. Over the years security on the trucks has gone down because of the industry, the lowest bidder competition. We’ve tried to intervene, talked ot the Minister of Public Security over the years to have some regulation.”

He said that security truck holdups are cyclical.

Vaillancourt wants three people on the trucks, with one person specifically tasked to watch possible threats. He said that trucks routinely had three guards aboard until the late 90s when the dual guard system was imposed in order to keep costs down and secure contracts.

Vaillancourt told CTV Montreal that workers are routinely traumatized when involved in such incidents.

Some never return to the job. “It’s hard on the family and everyone involved,” he said.

'Strange situation'

Security analyst Chris Lewis told CTV News Channel that the information released so far is "sketchy" and may suggest that the guards were robbed outside of their car.

"It’s a strange situation in that normally only two guards get out of those armoured trucks. At least one stays inside, locked, and of course has got a radio and phone and additional weapons," Lewis said. "So if the guards had $400,000 plus on them and that’s what was taken that seems kind of odd to me in itself."

But, Lewis said, the lack of detail does not necessarily mean that the crime was an inside job.

"It looks different but that doesn’t mean that the guards were involved in any way. It may just be the police are withholding details," he said.

Lewis also said that the two guards would have been well-trained to deal with robbery situations.

Garda told CTV Montreal that it is co-operating with the police investigation, but did not share any more information.

With a report from CTV Montreal’s Maya Johnson and files from the Canadian Press