In an interview aired Thursday on "Byline With Brian Lilley" on Sun News Network, Harper expressed his condolences to the friends and families of the victims of Wednesday's attack in Benghazi.
"What happened is extremely disturbing; it's horrific, disgusting," Harper said.
"Diplomats do not sign up for military service; we assume that our diplomats can conduct the business of their respective countries free from fear of persecution or violence."
Canada's decision last week to shutter its embassy in Iran — a now-prescient move that appeared sudden and inexplicable at the time — was and remains "overwhelmingly" supported by Canadians, Harper said.
In Iran, "this kind of thing not only happened in the past, but happened at the instigation of the government," he said. The decision was made because it was no longer possible to guarantee the safety of diplomatic personnel there, he added.
The violence roiling the Mideast "should just underscore why we have to take these actions from time to time."
What's more, Harper said, no one should be surprised to see that last year's dramatic popular uprisings in places like Egypt haven't resulted in stable democracies.
"The development of democratic societies, traditions, institutions is a process that requires a lot of work, and obviously the situation varies radically from country to country," he said.
"Mob rule is not democracy. Just because there's a popular overthrow of a dictator does not mean the next regime will necessarily be based on democratic norms. So this is something that we're watching and obviously requires our continued engagement and work."
U.S. diplomatic missions across the Middle East are on high alert following Wednesday's attack, fuelled in part by an American anti-Islam video that has sparked violent protests in Yemen and elsewhere in Egypt.
Secretary of State Hillary Clinton has denounced the video in hopes of pre-empting further turmoil.
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