In an interview with French broadcaster TVA, Harper calls the deaths a "great tragedy" that's almost impossible for anyone — notably anyone with children of their own — to comprehend.
"It's very sad. As a father, it's very difficult to watch these images of children who were killed," Harper said.
"Over the weekend, I stopped watching that. It's almost impossible to imagine how someone could do something like that to children. It's a great tragedy, and we're using the opportunity to remind our children of our love."
Harper said it's worth remembering that Canada has a stronger, stricter gun control system than exists in the United States, even without the long-gun registry.
"We will not change the basis of this system. Actually, we have reinforced certain parts," he said.
The Conservative government abandoned the registry earlier this year on the grounds it was a costly and ineffective affront to law-abiding gun owners.
Harper said Canada continues to require gun licences and that handguns and restricted weapons be registered.
"We will keep this system that works. That's the important thing, to have controls that work," he said.
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