Rob Ford Rehab Chicago
Toronto Mayor Rob Ford withdrew his application to enter the USA where he was supposed to go to rehab. Reuters

Embattled Toronto Mayor Rob Ford took a plane to go to rehab in the US but, upon landing, suddenly decided to turn back to Canada and his whereabouts are currently unknown.

Ford boarded a plane to Chicago last week after announcing that he was to seek professional help for alcohol abuse, his lawyer, Dennis Morris, said.

The mayor reportedly landed at the city's Midway International Airport but never passed the US border controls.

"He voluntarily withdrew his application to enter the USA," the Consul General of Canada in Chicago told The Globe and Mail newspaper. "He was not denied entry, per se."

Ford's brother, Doug, a Toronto city councillor, said the mayor booked in a rehab facility but refused to disclose where or comment on what happened at the US border.

"The most important thing, everyone who is concerned if he's in rehab, the answer is yes. As for his whereabouts that's personal and that should stay with Rob," Doug Ford said.

"He's doing well," he added.

The US Department of Homeland Security website says that an individual might be denied entry if, he/she is found guilty of a criminal offence or "admits having committed... a violation of (or a conspiracy or attempt to violate) any law or regulation of a State, the United States, or a foreign country relating to a controlled substance".

Last year, the conservative politician admitted that he had smoked crack cocaine during one of his "drunken stupors" following reports that Canadian police retrieved a video allegedly showing him smoking crack.

Ford is last known to have entered the US in March when he flew to Los Angeles to appear on a TV show.

Last week, he announced he was to take a leave of absence from his re-election campaign to seek help after a second video allegedly showing him smoking crack cocaine emerged.

"I have a problem with alcohol, and the choices I have made while under the influence. I have struggled with this for some time," Ford said.

"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 per cent committed to getting myself right."

The Globe and Mail reported Ford was seen smoking what a drug dealer described as crack cocaine from a copper-coloured pipe in his sister's basemen in footage reportedly recorded two weeks ago.

Ford, who previously repeatedly ignored calls to enter rehab or resign, is seeking re-elections in October.

Ford, who previously repeatedly ignored calls to enter rehab or resign, is seeking re-election in October.