Toronto police fanned out across the city Thursday due to “unconfirmed and uncorroborated information of a threat” to multiple tourist attractions including the CN Tower, according to police communications obtained by CTV News.

By Thursday night, police said they had resumed normal operations but the public would “continue to see a police presence around the Rogers Centre as part of our 2018 downtown security plan.”

It ended a day of uncertainty for the public as to what -- if anything -- the potential threat might have been.

Details of the unconfirmed threat were included in a bulletin sent to police supervisors and later shared with officers. The bulletin said there was “presently no information with respect to the identity of the perpetrator(s) and whether or not they are affiliated with a known extremist group.”

The notice emphasized that “at this time there is no corroborating information that validates this threat.”

Regardless, police supervisors were reminded that “tactics employed by extremists have included the use of vehicles, small arms, knives and/or explosives.”

“Tourist centres, areas of large public gatherings, and critical infrastructure remain as vulnerable targets for terrorist/extremist groups and their sympathizers who wish to stage high-profile attacks,” the bulletin read.

Police received the information Wednesday, the bulletin clarified.

Police officers on foot and horseback were stationed across the city at transit hubs, high-traffic areas and tourist destinations, including the Rogers Centre, the CN Tower and Ripley’s Aquarium. North of the city, police established a mobile command post at the parking lot of Canada’s Wonderland in Vaughan, Ont.

U-Haul International released a statement saying they were contacted Wednesday by Ontario Provincial Police “with a request to remain vigilant in reporting suspicious activity in the Toronto area.”

“As a result, and at the request of police, U-Haul issued a reminder to our Ontario team members to continue being mindful of suspicious behaviour and reiterated instructions on how to report such behaviour to police,” vice president of communications Sebastien Reyes said in a statement.

An earlier draft memo was sent to some Toronto police officers saying that a threat was made about a “potential vehicle ramming attack” in the busy CN Tower area. But police later said in a tweet that the memo was a “draft operational plan never approved.”

“Our officers were provided with most up to date/accurate info this morning, as was public,” Toronto police tweeted.

The news broke around 9 a.m. Thursday in a tweet from Toronto Police that alerted the public of increased police presence in the downtown core due to an “unconfirmed, uncorroborated piece of information.”

Police refused to specify what type of information or threats they were investigating, but said that the CN Tower and venues in the surrounding area will remain open.

"Whenever we have report of a potential risk we take that seriously," Acting Supt. Michael Barsky told reporters at a morning press conference. "The police presence in this area is simply to ensure that the public can enjoy and come down to this area unimpeded and without any worry."

Emergency Task Force officers were seen near the CN Tower Thursday, while officers on bicycles patrolled the area around the nearby Rogers Centre. Go Transit also dispatched extra safety officers to Union Station.

A large crowd gathered outside the Rogers Centre Thursday evening for a Foo Fighters concert. Dump trucks blocked off the area and dozens of police officers were on the scene.

Many attendees who spoke to CTV Toronto were aware of the heightened concern and still chose to attend.

“It’s concerning. But you’ve got to still live your life,” one woman said.

Kaela Rivington, a tourist visiting from Winnipeg, said the increased police presence was alarming.

“Well it’s scary. We’re just out here waiting in line. We weren’t sure what was going on, and there’s been a lot of police around,” Rivington said.

Security in the area of the CN Tower has been ramped up since the Toronto van attack in April, which killed 10 people and injured 16 others. Concrete barriers were installed to separate the sidewalk from the road.

Toronto Mayor John Tory, Ontario Premier Doug Ford and federal Public Safety Minister Ralph Goodale all said that they are monitoring the situation.

With files from CTV Toronto and The Canadian Press

We are responding to an unconfirmed, uncorroborated piece of information relating to the GTA. As a result of this information, you will see an increased number of police officers throughout the city and, specifically, in the downtown core ^sm — Toronto Police (@TorontoPolice) July 12, 2018