The FTC said the behavior violated terms of the settlement Google reached with the agency last year over its now-defunct Buzz social networking service.
The FTC ordered Google to disable all the tracking cookies by next year. Tracking cookies are snippets of computer code that collect information about how users browse the Web and can be used to show users ads based on their browsing history.
The FTC said that Google told Safari users that because the browser blocks third-party cookies, they did not need to opt out of online tracking. Yet Google in fact placed a temporary cookie on computers, tablets, and mobile devices, a privacy breach first reported by Stanford researcher Jonathan Mayer.
In reaching the settlement, Google did not admit liability.
"We set the highest standards of privacy and security for our users," Google said in an e-mailed statement. "The FTC is focused on a 2009 help center page published more than two years before our consent decree, and a year before Apple changed its cookie-handling policy. We have now changed that page and taken steps to remove the ad cookies, which collected no personal information, from Apple's browsers."
Google did not contest the facts in the FTC complaint and its defense that it was unaware of what it was doing was "immaterial," David Vladeck, director of the FTC's bureau of competition, said on a conference call Thursday after the announcement.
The FTC said it would continue to monitor Google to ensure that it does not engage in deceptive practices. Google has 19 years left on the 20-year settlement it reached last year that prevents the search giant from misrepresenting how it handles user information and requires Google to submit to regular privacy audits.