In a video released on YouTube, the group Anonymous said Toronto will be "removed from the Internet" unless the city promises to leave the protesters alone.
Mayor Rob Ford asked the occupiers this week to dismantle their tent city in St. James Park.
The mayor's office reaffirmed his position Saturday when asked about the hackers' warning.
"The mayor and city manager have been very clear over the past week _ it's time this came to a peaceful conclusion," the statement read.
"They do not have a permit and we are asking them to leave."
Demonstrators with the Occupy group have brushed off the mayor's plans and promised to regroup at another location if evicted.
A few protesters tried to set up a new base in the park behind the Ontario legislature over the weekend, but their efforts were cut short.
Police shut down the fledgling camp Saturday night and brought the demonstrators back to the original site. (CFRB, The Canadian Press)
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