Canada's electronic eavesdropping agency reportedly tracked the wireless devices of thousands of travellers by using information gleaned from free internet service at a major Canadian airport.
The CBC is reporting the revelation is contained in a top secret document retrieved by U.S. whistleblower Edward Snowden.
The network says the document indicates the Communications Security Establishment Canada was given information taken from wireless devices using the airport's free Wi-Fi system over a two-week period.
It's not clear which airport was involved.
The document shows the CSEC was then able to track travellers for a week or more as they showed up in other Wi-Fi locations in cities across Canada.
A CSEC statement given to the broadcaster would not confirm or deny the CBC report.
Ontario Privacy Commissioner Ann Cavoukian told the CBC it's "unbelievable" CSEC would engage in that kind of surveillance of Canadians saying it "resembles the activities of a totalitarian state."
Earlier this week, interim federal privacy commissioner Chantal Bernier said the CSEC should tell Canadians more about what it's doing.
The document the CBC obtained said the Wi-Fi exercise was part of a pilot project done alongside CSEC's American counterpart, the National Security Agency. According to the document, the agency tracked metadata including the location and telephone numbers of calls made and received but not the content.