A bomb-sniffing dog was brought through Toronto Mayor Rob Ford's office on Monday, after a email bomb threat came in that urged him to resign.

While police investigated the threat, no evacuation took place and no explosives were found.

Ford told media outside of his office that the email warned that he and his brother had "24 hours to vacate" otherwise "city hall will blow."

Bomb sniffing dogs enter the mayor's office.

Bomb-sniffing dogs enter the mayor's office. (Steve D'Souza/CBC)

The mayor said the "disturbing" email indicated explosives had already been set up around the building. Doug Ford, who represents Etobicoke North, is the mayor's campaign manager as his brother seeks a second term as mayor in the Oct. 27 municipal election.

When asked if the police advised him to go public with the threat, the mayor responded he was "acting on his own advice."

"I just want to let the people of this great city know what's going on," he said.

Coun. Paula Fletcher said Monday that the city has a protocol for dealing with such threats and that protocol does not prohibit officials from disclosing them.

Fletcher said she hoped the mayor knew the threat was not real before he publicly disclosed it.

"I hope he's followed what I would call the good rules, or good common sense. And since we're still here in the building, I'm going to assume it was just an angry letter from a disturbed individual," she said.

The investigation into the threat continues.

With files from The Canadian Press and the CBC's Steven D'Souza