Organisers of the PGA Tour's Canadian Open, the final tuneup for June's US Open, were reassessing options on Wednesday in the wake of Toronto city officials canceling event permits.

World No 1 Rory McIlroy is the defending champion at the Canadian Open, the longest-running tour event outside the US Open and Open Championship, dating to 1904.

Toronto officials voided all event permits and access to city services through 30 June because of the coronavirus pandemic.

That would not impact pro sports teams or Toronto's IndyCar race, set for 12 July on the city streets, but would hit the Canadian Open, set for 11-14 June at St. George's Golf and Country Club.

"Together with the PGA Tour, we are assessing this recent development along with other challenges posed by Covid-19 to determine the best course of action for the Canadian Open," the tournament announced in a statement Tuesday night. "We will make further announcements in the coming week."

For now, it's set to be the last tour stop before the US Open, scheduled for 18-21 June at Winged Foot in suburban New York, the hardest hit US city by the deadly disease.

"We appreciate the factors that led to this decision, in particular that all city resources are being directed to support our communities during this unprecedented health crisis," the Canadian Open statement said.

The next scheduled PGA Tour event is 21-24 May, the Charles Schwab Challenge at Colonial, followed by a stop in Detroit and the Memorial tournament, hosted by 18-time major winner Jack Nicklaus, at Dublin, Ohio the week before the Canadian Open.

The only years the Canadian Open was not played were 1943-44 due to World War II and 1915-18 due to World War I.