Mayor Brian Bowman says he has no concerns about the potential Winnipeg Police Service use of electronic surveillance devices capable of intercepting mobile communications data.

According to documents obtained by CBC News, federal public safety officials approved a licence that allows Winnipeg police to purchase devices designed to intercept private communications of citizens.

Bowman, who worked as a privacy lawyer before he was elected mayor, said Wednesday he hasn't been advised about the potential use of these devices by Winnipeg police, and he has no intention of making any inquiries about them.

"The Winnipeg Police Service operates within the law and I have confidence that any technologies they're utilizing will be used in accordance with the Charter of Rights and Freedoms," Bowman said at city hall after an executive policy committee meeting.

The mayor noted the Winnipeg Police Board, not city council, provides oversight of the Winnipeg Police Service. He said he did not examine the use of the fake cell towers when he worked as a privacy lawyer​.

Privacy watchdogs, however, have criticized the lack of regulation of these devices, which can harvest data from mobile phones indiscriminately. Wiretaps, in contrast, only target surveillance subjects.

While many technologies exist, one in particular is controversial for its known ability to invade privacy. Often referred to as international mobile subscriber identity (IMSI) catchers, these tools masquerade as cellular towers and intercept signals from mobile phones within an area by casting a wide net that can include non-intended targets.

Documents about the devices, gathered through freedom of information requests and provided to CBC News by Ottawa-based researcher Ken Rubin, were stripped of information that could identify the manufacturer or the capabilities of the machines.

This undated handout photo provided by the U.S. Patent and Trademark Office shows the StingRay II, manufactured by Harris Corporation, of Melbourne, Fla., a cellular site simulator used for surveillance purposes. (U.S. Patent and Trademark Office/Associated Press) The documents show the assistant deputy minister of Public Safety Canada's national security branch approved a licence that would allow the Winnipeg Police Service to purchase devices from an undisclosed company for one year, beginning June 23, 2016.

The Winnipeg Police Service would not say whether it uses IMSI catchers. The office of the Manitoba ombudsman declined to comment on the privacy issues posed by use of the surveillance tools.

Former Ontario privacy commissioner Ann Cavoukian, who served three terms as a public privacy watchdog before becoming the executive director of the Privacy and Big Data Institute at Toronto's Ryerson University, called the use of the devices appalling.

"No one is intending to have their communications from the cell towers shared with the police," Cavoukian said in a Tuesday interview aired on CBC Radio's Up To Speed.

There is no transparency surrounding the use of the devices, she said.

"It is staggering to me that this is being approved by the government," she said, noting wiretaps of landlines require more oversight.