SAN FRANCISCO — Google Inc. disclosed on Friday that it has mistakenly collected private information about Internet users’ data, including the Web sites they visit, from unprotected wireless networks as it compiled information for part of its mapping service.

Google said the discovery that it has been collecting data about what users are transferring over Wi-Fi networks came as part of a reexamination prompted by a request from a German regulator to audit data the company’s cars collect as they gather information for the Street View feature of Google’s maps.

Street View enables users to see close-up, digital images of locations.

Google deploys cars mounted with cameras and equipment to take photos and collect data about wireless networks. That network data is intended to enable Google to identify network names and enhance location-based services.

But in addition to data about network names and equipment, Google said Friday it has also been inadvertently collecting so-called “”payload”” data, or what users transfer and receive over wireless networks, such as particular Web sites.

The company’s effort to gather Street View data has come under heavy criticism from privacy advocates, particularly in Europe. Germany’s Data Protection Authority, which requested the audit of Google’s Street View data, has raised concerns about the service in the past.

Google had previously responded to the data protection authority’s concerns by saying that while it collected certain types of network data, it avoided payload data. In an online posting on April 27, Google stated explicitly that it did not collect payload data.

Google chalked up its mistaken collection of personal data on Friday to inadvertently including a piece of code in software used by its Street View team.

“”We want to delete this data as soon as possible, and are currently reaching out to regulators in the relevant countries about how to quickly dispose of it,”” Google said in a statement issued after the markets closed.

“”Maintaining people’s trust is crucial to everything we do, and in this case we fell short.””

Google said it will now stop its Street View cars from collecting Wi-Fi network data entirely.