Security officials are on alert with intelligence agencies learning about possible terror attacks on Canadian soil.

According to reports, authorities heard of a plan by extremists to carry out “knife and gun” attacks on Canadians.

A report by American network NBC mentioned the U.S. embassy in Ottawa and an unspecified shopping mall somewhere in Canada as potential targets of a violent plot by terrorists. The report was later changed, removing reference to specific places.

Michael Zekulin teaches at the University of Calgary and specializes in examining radicalization.

“This is the darker side of terrorism we talk about,” he said.

“The reality however is, is when you're talking about an individual or two or three individuals who are content to use standard everyday things like kitchen knives for example and go to malls - that is a lot more difficult for intelligence and law enforcement to detect and prevent,” said Zekulin.

Prime Minister Harper won't discuss Canada's national security operations at home, but says it's clear that Islamic State extremists pose a very real threat.

Harper says the Conservatives will be bringing in additional measures to help security agencies to monitor threats, but didn't elaborate on what those measures might include.

- with a report from Josh Crabb and files from The Canadian Press