Toronto mayor Rob Ford is to take an immediate leave of absence to seek help for alcohol as a report surfaced about a second video of him smoking what appears to be crack cocaine.
Mr Ford said he would also take leave from his campaign for re-election. One of his rivals called on the mayor to resign.
Mr Ford said in statement: "I have a problem with alcohol, and the choices I have made while under the influence. I have struggled with this for some time.
"I have tried to deal with these issues by myself over the past year. I know that I need professional help and I am now 100% committed to getting myself right," he said.
The Globe and Mail newspaper said it has viewed a second video of Mr Ford smoking what appears to be crack cocaine in his sister's basement.
The national newspaper said two reporters viewed the video, from a self-professed drug dealer, showing Mr Ford taking a drag from a pipe early on Saturday morning.
The video is part "of a package of three videos the dealer said was surreptitiously filmed around 1.15am and which he says he is now selling for 'at least six figures'", the paper reported.
Mr Ford did not mention the reported video in his statement.
John Tory, who is running against Mr Ford, said he is relieved the mayor is seeking help but he should resign.
"Like Torontonians across the city, I am deeply disappointed by these revelations of Mayor Ford's behavior," Mr Tory said. "For the good of the city, I call on Mayor Ford to resign."
News reports of the existence of an earlier video of the mayor apparently smoking crack first surfaced last May, igniting a media firestorm.
Mr Ford's lawyer, Dennis Morris, said he spoke to the mayor and he has accepted that he has a problem.
"He acknowledges he has a substance abuse problem and he wants to do something about it," Mr Morris said.
Mr Ford, who launched his campaign for re-election earlier this year, acknowledged last year after months of denials that he smoked crack in a "drunken stupor" after police said they obtained a video that appears to show him doing so. The video has never been released.
Mr Ford has careened from one scandal to another, becoming a national embarrassment for many Canadians.
The Toronto Sun said yesterday that it had obtained an audio recording of him making offensive remarks about other politicians at a bar on Monday night.
Mr Ford has refused to resign, despite mounting pressure after a string of incidents, from public drunkenness to an appearance in another video that showed him threatening "murder" in an incoherent rant. Toronto's city council has stripped him of most of his powers.
He said last year that he quit drinking alcohol after having a "come to Jesus moment" but later acknowledged that he drank again. A number of recordings of the mayor intoxicated have surfaced since.
Mr Ford acknowledged "rocky moments over the past year" during his official campaign launch earlier this month but vowed to fight harder than ever to win re-election.
The mayor, who was the first to register as a candidate in January, invoked the spirit of second chances during a speech in front of supporters.
In in his statement yesterday, he asked for continued support. "I love the people of Toronto, I love being your mayor and I hope you will continue to stand by me," he said.
Comedian Jimmy Kimmel, who has repeatedly poked fun at Mr Ford and hosted him on his show, tweeted that he was concerned about.
"All jokes aside, I hope@TOMayorFord really does get the help he obviously needs," Mr Kimmel tweeted.