TORONTO -- Equifax Canada's customer service agents are telling callers that only Canadians who have had dealings in the United States are likely to be affected by the massive hack announced last week.

The credit monitoring company's call centre staff say that Canadians who have Equifax accounts in the U.S. could be at risk of having their data compromised, such as those who have lived, worked or applied for credit south of the border.

The Canadian Press made multiple calls as consumers to Equifax Canada's customer service line and were told that consumers whose credit files were not checked outside of Canada are unlikely to be part of any breach.

Equifax Canada did not immediately respond to requests for comment.

Equifax said last Thursday a security breach occurred over the summer that compromised the private information of up to 143 million Americans, along with an undisclosed number of Canadians. But the company has been tight-lipped about further details, including how many Canadians may have been exposed.

Equifax Canada's website says that "only a limited number of Canadians may have been affected" and "the breach is contained."

"We are working night and day to assess what happened," the credit monitoring company says on its Canadian website.

Canadian and American credit files must be kept separate due to differences in the various laws within the U.S. and Canada, according to the Equifax Canada website.

However, American companies can pull Canadians' files in Canada with consumers' permission, according to credit risk expert Mike Morley.

"Let's say you're a Canadian applying for a mortgage in the U.S. for your cottage... They will make a decision based on your Canadian credit information," Morley said.

That would generate a U.S. credit file for the consumer, he said.

Morley added that Canadians who live and work south of the border would have their credit history in Canada in various situations, including when applying for a credit card, or even by a potential employer or landlord.