Threats of student protests have forced organizers of the Canadian Grand Prix to cancel the free opening day of the event.

Formula One fans were to have had access to Circuit Gilles Villeneuve at the "Open House" event Thursday.

Statement from the Canadian Grand Prix

"Considering the various disruption threats made public recently, the free admission and the naturally openness character of the ‘Open Doors’ day, revealed some risks that we could not neglect. Under these circumstances, canceling the ‘Open Doors’ day was the only action we could take. Unfortunately, for the fans and our spectators, it was impossible to escape from such responsibility."

Instead the event was scrapped due to security concerns.

"We did receive some direct threat on the event," said François Dumontier, president of the Canadian Grand Prix.

He says the organization has already lost some money due to security concerns.

"Our ticket sales are down over the last month or so. People didn't buy the tickets, saying that they were afraid to come to Montreal."

The student group CLASSE has suggested the race be used as a platform for the protesters' demonstrations over tuition fees.

Quebec Premier Jean Charest in turn has been critical of threats toward the race that generates an estimated $100 million in revenue for the city.

More than 300,000 spectators are expected to attend the event, which runs June 8 to 10.

With files from CBC News