OTTAWA—Canada’s spy agency has backtracked on its promise to reveal to a Senate committee how many Canadian journalists it spied on in the past, citing operational security.

The Canadian Security Intelligence Service (CSIS) said while it “appreciates the importance of the question” to Canadians and the Senate committee on national security and defence, “we regret that we cannot confirm whether journalists have been the subject of any CSIS investigation.”

Conservative Sen. Claude Carignan, who had pressed two top CSIS assistant directors on the issue last month, called it a “bizarre response” and a “serious” breach of an undertaking to a parliamentary committee. He suggested it implies that surveillance of journalists is either still ongoing or has been recently suspended.

“How can it harm operations if you don’t have any operations ongoing?” he said in an interview, likening the CSIS reply to “figure skating.”

Carignan, who has tabled a private member’s bill to protect journalists’ sources, wondered if there had been surveillance operations of media that are currently suspended, especially after the controversial practice surfaced in Quebec where provincial and Montreal city police were revealed to have spied on several top investigative reporters and columnists, apparently in search of police leaks.

The CSIS statement to the committee this week said CSIS recognizes it “has a duty to fulfil its mandate in a manner that upholds Canadian law and values.

“However, we also have a duty to identify and advise government of threats to our national security, and exercise our authorities set out in law to fulfil this mandate. Any individual engaged in threat-related activities may be subject to this kind of lawful investigation, irrespective of their profession.

“While CSIS can discuss elements of its relevant policy framework, we cannot provide information regarding whether anyone may or may not have been the subject of investigation. To do so would compromise the integrity of our operations and jeopardize our ability to fulfil the mandate given CSIS by Parliament.”

It repeats the CSIS and government line that, as a matter of policy, there are many levels of approvals before any surveillance is undertaken on sensitive sectors, including media, academia and trade unions. “Safeguards within this policy include senior levels of approval, special requirements for consultation, and a requirement to advise the (public safety) minister,” says CSIS.

Last month, Brian Rumig, assistant director of CSIS operations, conceded it was possible CSIS had in the past spied on reporters either directly or indirectly, although it has publicly said no reporters are currently under surveillance.

“We would not investigate someone simply because they are a journalist,” said Rumig. “I’m going to guess . . . that in the past in the course of 30 years of the service being in existence yes, there might have been a journalist who, because of his or her activity in support of threats to the security of Canada, might have been investigated by us. Currently I don’t know those numbers,” he said.