Toronto's embattled mayor offered an emotional apology for his "mistakes" Tuesday hours after admitting he has smoked crack cocaine while in office, but said he has no plans to step down.

After months of denying he's used drugs, Rob Ford shocked Canada's largest city with his revelation that he had smoked crack about a year ago when he was "in a drunken stupor."

On Tuesday evening, a visibly troubled Ford said he was sorry.

"I know what I did was wrong and admitting it was the most difficult and embarrassing thing I have ever had to do," he said.

"To the residents of Toronto, I know I have let you down. And I can't do anything else but apologize, and apologize."

Ford has been under intense scrutiny since May, when two media outlets reported the existence of a video that they said appeared to show the mayor smoking crack.

Last week, Toronto's police chief said authorities had recovered a video of the mayor with images that corresponded with those media reports.

Ford said Tuesday that he kept his drug use from his family, his staff and his colleagues at city hall because he was "embarrassed and ashamed."

"These mistakes will never, ever, ever happen again," he said. "I was elected to do a job and that's exactly what I'm going to continue doing."

Earlier Tuesday Ford said, "Yes, I have smoked crack cocaine. I've made mistakes in the past . . . I can't change the past. I can apologize."

He said it was probably "in one of my drunken stupors" about a year ago when he smoked the drug.

Earlier in the day, a furious Councillor Doug Ford called a news conference outside the mayor's office at Toronto City hall to lash out at Police Chief Bill Blair.

He accused the chief of bias for the personal comments that the chief made last week about a videotape that apparently depicts his brother, Mayor Rob Ford, smoking crack.

"We have the most political police chief that I have ever seen," thundered Councillor Ford. "He believes he is the judge, jury and executioner. This compromises the chief."

Councillor Ford, who asked city staff to move a lectern to the hallway to give a spot to speak, also called on Andy Pringle, a member of the police board, to resign, saying his friendship with Chief Blair compromised his objectivity.

Councillor Ford's comments aren't a huge surprise. On Monday night, he went on The Arlene Bynon Show on SiriusXM Canada, to discuss recent events. He stressed how much he and his brother support the "front line" police officers who work so hard out there. This was at least the second time in as many days that the Councillor and/or the Mayor spoke well of "front line" officers.

"I do not have confidence in Andy Pringle," he said. "He went on a fishing trip with the chief."

One reporter asked Mr. Ford whether it was wise that he attack the chief of police while police are investigating Mayor Ford.