Toronto Mayor Rob Ford under mounting pressure to resign

Toronto's mayor has faced angry protesters - and mounting calls to quit - as he arrived for work a day after he admitted smoking crack cocaine.

One of Mayor Rob Ford's veteran policy aides resigned on Wednesday, the latest in a string of defections since May.

Meanwhile, even Mr Ford's allies on the city council say they have lost confidence in him.

Officials in Canada's largest city cannot legally remove Mr Ford unless he is convicted of a crime.

More than 200 chanting demonstrators were gathered outside city hall as Mr Ford arrived for work shortly after midday on Wednesday. He entered his office via a back stairway.

'Stubbornly refused'

City Councillor James Pasternak says he and several colleagues are asking Deputy Mayor Norm Kelly to approach Mr Ford again about resigning, in the hopes of a "dignified exit".

Another councillor, Janet Davis, said the mayor had "stubbornly refused to listen to everyone across the city to step down".

"The mayor has got to come to the conclusion himself that he has to step down," she said on Wednesday.

Ontario Premier Kathleen Wynne has expressed concern about Mr Ford's personal issues, but she stopped short of calling on him to stand aside.

City Councillor Denzil Minnan-Wong, who serves on Mr Ford's executive council, is proposing a motion asking Mr Ford to take a leave of absence.

He says he knows it is a symbolic move, but "the right thing to do is for council to take a clear position".

"I remain concerned that there's more information that's going to come out," he told reporters. "I'm troubled by that and that it will hurt this city even further."

On Wednesday, Canadian media reported that Brooks Barnett, a Ford police advisor, was no longer on the mayor's staff.

Mr Ford's office did not offer details other than to confirm Mr Barnett's departure.

After months of ducking the question, Mr Ford acknowledged on Tuesday for the first time that he had smoked crack "probably a year ago" while in a "drunken stupor".

He said he was "embarrassed" by his behaviour, but vowed to run for re-election.

The mayor has not been charged, but city police chief Bill Blair has said authorities are in possession of a video which apparently shows Mr Ford smoking crack.

Mr Blair has also said police are in possession of a second clip, but will not describe its contents.

The allegations of drug use first surfaced in May when journalists with the gossip website Gawker and the Toronto Star reported seeing the footage.

It is unclear when the video of Mr Ford - described by the Toronto Star as "clearly impaired" and "incoherent and rambling" before smoking from the pipe - was shot.

But it was recorded with a phone camera, suggesting it could not be more than a few years old. And in it Mr Ford expresses his distaste for Justin Trudeau, a young parliamentarian elevated to Liberal Party leader less than a month before reports of the video surfaced.

Just over 1% of all Canadians 15 years or older used crack cocaine in the past year, according to a Health Canada survey quoted by broadcaster CBC.