A petition calling on TfL to reverse its decision not to renew Uber's London licence reached half a million signatories just after midday today.
Khan said: “I have every sympathy with Uber drivers and customers affected by this decision but their anger really should be directed at Uber.
"They have let down their drivers and customers by failing, in the view of TfL, to act as a fit and proper operator.
“I suspect it will take some time before this situation with Uber fully plays out. In the meantime, I will continue my work to help support innovative businesses in London and to create a vibrant and safe taxi and private hire market.”
According to Change.org, the site on which the pro-Uber petition is hosted, said it is the fastest growing petition in the UK this year.
“The speed with which this grew shows how powerful online campaigning can be," Kajal Odera, UK director of Change.org told the Press Association
“In just 24 hours we’ve seen hundreds of thousands of people start and sign petitions on either side of the Uber/TFL debate."
Several MPs have also waded into the debate.
Yesterday the Conservative MP and minister for London Greg Hands tweeted his opposition to the move
On Uber "At the flick of a pen Sadiq Khan is threatening to put 40,000 people out of work and leave 3.5 million users of Uber stranded" 1/3— Greg Hands (@GregHands) September 22, 2017
Uber has previously been criticised by a cross-party panel of MPs, who urged TfL to strip the ride-hailing app of its licence.
Yesterday Labour MP for Ilford North Wes Streeting said TfL's ruling was "courageous".
Why TFL were right not to renew Uber's licence and why their business model should concern all of us. pic.twitter.com/SlgogvBaPM— Wes Streeting MP (@wesstreeting) September 22, 2017
But Chris Philp, Conservative MP for Croydon said it was a "step too far".
Cancellation of Uber licence step too far. Issue to address but this tips 40,000 drivers out of work & denies 3.5m Londoners cheap travel— Chris Philp MP (@CPhilpOfficial) September 22, 2017