Prime Minister Stephen Harper emerged Monday as a proponent of ethnic diversity as a shield against terrorist attack.

Harper said there have been misguided suggestions since the arrest in early June of 17 people in Ontario on terrorism-related charges "to the effect that Canada's open and culturally diverse society makes us more vulnerable, a more vulnerable target for terrorist activity."

Prime Minister Stephen Harper speaks to World Urban Forum in Vancouver.

"I believe that exactly the opposite is true," he told a United Nations forum on urban problems, drawing applause from many of the 5,500 delegates in Vancouver. "Canada's diversity, properly nurtured, is our great strength."

Canada has been spared the attacks experienced by New York, London, Madrid and many other cities thanks to "our superb domestic security forces," but its best protection is its freely mingling ethnic groups, he said.

"Visit almost any city in the country and you'll find Chinatown, a Little Italy, a French quarter, an East Indian commercial or residential enclave. These and many more reflect the amazing ethnic diversity of Canada, but they flourish because they are not isolated from the larger community.

"On the contrary, the shops in Chinatown, the restaurants in Little Italy attract people from all over. We've largely avoided ghettoization, the bane of urban existence in so many other places, the impoverished crime-ridden and ethnically polarized no-go zones.

"It is true that somewhere, in some communities we do find promoters of terror, people who use cultural, religious symbols to perpetrate violent crime. They abhor open societies, pluralist societies, democratic societies, because they advocate the exact opposite: a closed, homogeneous, dogmatic society.

"But they and their vision will be rejected. … It will be rejected by men and women of generosity and goodwill in all communities.

"It will be rejected most strongly by those men and women in the very community the terrorists claim to represent, as we have seen already in Canada since those arrests."

Canada, he said, is a place where people of all backgrounds live and work together, "a place in which where you are going matters more than where you came from.

"Our government will do all we can to make our society secure and to make sure that terrorism finds no comfort in Canada, and we will do so by preserving and strengthening the cultural diversity that makes us strong."