"I believe that it is necessary and prudent to put in place enhanced security precautions to ensure the safety of our citizens and of our city," Blair told a news conference Wednesday, hours after a soldier was killed in an attack in Ottawa.
"Accordingly, Torontonians will see today and over the coming days a very visible police presence at various public institutions and public spaces."
Those public institutions include Queen's Park, Toronto's city hall, courthouses, consulates, the subway system as well as military facilities, Blair said.
At the same time, he stressed that there was no specific or identified credible threat to any individual, group or public institution in Toronto at this time.
Blair said the aim was to reassure people who are obviously concerned at what happened in the capital earlier in the day.
At the National War Memorial in Ottawa, a reservist from Hamilton was killed by a masked, rifle-wielding gunman, who then moved up the street to launch an attack on nearby Parliament Hill, in which at least two people were injured.
Just two days earlier, a man ran down two soldiers south of Montreal, killing one of them.
Blair said he had asked all of his officers to be vigilant in the wake of the attacks.
Calling it a "difficult day for our country," he also urged the citizens of Toronto to be vigilant as well.
"If you see something that concerns you, or if you become aware of anything suspicious, please do not hesitate to call and we will respond," Blair said.
Vowing not to be complacent, Blair also said he had cancelled some police leave to enhance security.
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