The head of Canada's spy agency told a Senate committee today that his agency has used its extraordinary powers to disrupt extremist plots close to two dozen times since the fall of 2015.

Michel Coulombe, director of the Canadian Security Intelligence Service, made the admission to the national security and defence committee, revealing for the first time how frequently this power was used.

Canada's spy agency was granted the power to disrupt suspected plots rather than just relay information about those plots to the federal government and the RCMP when Bill C-51 became law this past summer.

"We wanted to work in a responsible way, because it was a new mandate for us," Coulombe said in French. The new powers had been used "fewer than two dozen times," he said.

Coulombe was asked by members of the committee if he thought CSIS would use the powers again.

"Yes, however, once again this is a tool among many, a tool that is used in consultation with our partners. Before taking any threat mitigation measures, we communicate with the RCMP to make sure it will not disrupt their inquiries," he said.

As an intelligence agency, CSIS traditionally did not have the power to enforce the law. Its role has been to pass on intelligence to other branches of government. When Bill C-51 became law, however, it gave the spy agency power to actively interfere with suspected terrorists if it has reasonable grounds to think a security threat exists.

Michel Coulombe tells Senate committee why radicalized Canadians returning to Canada are not being sent to jail. 1:15

Coulombe said it took a few months to set up governance structure before agents began using the powers in the fall of 2015.

The disruption powers allow CSIS to interfere with telephone calls, travel plans and bank or financial transactions. The agency can also disrupt radical websites and Twitter accounts of groups or people inside and outside of Canada.

Coulombe said that while CSIS would use the powers again, he would not say how many times it anticipated doing so, insisting "only time will tell."

He also noted that the federal government was conducting a national security review and after that review was completed a decision would likely be made that could affect this power and others.

Confidence in the system

Coulombe also spoke about the security screening of the 25,000 Syrian refugees that have come to Canada since the Liberals were elected. He said all underwent the same security screening that any refugee must face when coming to this country.

That system of clearing people for entry to Canada, said Coulombe, left him feeling "totally confident" in Canada's screening process, but he cautioned that just because refugees were screened it "doesn't mean that the risk was brought to zero."

Coulombe said that normally when a red flag pops up during refugee screening CSIS launches an investigation, digging deeper into the person seeking entry, but in the case of the Syrian refugees, those cases that caused concern were simply rejected.

"If a red flag came up, because of the tempo, we had no time to do this," he said. "That file was taken and was put aside. The moment there was a concern, that file was put aside and was no longer part of that 25,000."

Persons of interest

Coulombe was also asked to explain why, if his agency was aware of some 60 Canadians who had returned from abroad where they had engaged in terrorist activity, and there were as many as another 100 looking to go abroad, few arrests had been made.

"That's a question for the RCMP," he said. "Having information that someone was involved in threat-related activity overseas does not necessarily mean that that information meets the Criminal Code threshold.

"Is it enough for the RCMP to charge an individual, it's a pretty difficult thing to do. Between the threshold for us to launch an investigation and for the RCMP to charge someone, there is a fair bit of a difference here," he said.