OTTAWA  - Al-Qaida's new focus on "lone wolf" tactics is making it tough for Western intelligence agencies to prevent terror attacks, the head of Canada's spy service said on Monday.

In a rare admission that al-Qaida's switch to "individual jihad" was posing problems, the head of Canada's spy service said lone wolves are tough to detect because they do not belong to a larger network that might attract attention.

"When you have an individual who doesn't talk to anyone, you either need good luck - which happens sometimes - or for them to make a little mistake here and there," Richard Fadden, head of the Canadian Security Intelligence Service, told the Canadian Senate's anti-terrorism committee.

He said al-Qaida had decided to urge solo campaigns because it was too difficult to launch major operations such as the 9/11 terror attacks in the United States.

Canada, along with spy agencies in the United States, France, Germany and Australia, is trying to develop a greater understanding of what motivates solo attackers.

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