SAN FRANCISCO — Google Inc. found itself at the center of a national security controversy Thursday.
The Pentagon banned the Internet giant's digital-mapping vehicles from all military installations after detailed photographs of Fort Sam Houston in San Antonio appeared on Google Maps.
The Street View feature allows users to zoom in on 360-degree, ground-level views of neighborhoods, landmarks and other places that Google photographs from vehicles with roof-mounted cameras.
A message sent to all Defense Department bases and installations late last week warned officials not to allow Google vehicles access. Gary Ross, spokesman for the U.S. Northern Command, said sensitive imagery posted on the Web could pose a security threat.
"We don't have any issues regarding Google and their products, which are very useful tools," Ross said. "But the Street View provides clear imagery of control points, barriers, headquarters and security facilities that pose a risk to our force-protection efforts."
Google, based in Mountain View, Calif., said it erred in collecting the information from the base and has since complied with the military's request to take down the images.
A person familiar with the matter at Fort Sam Houston said a base official twice granted Google access, but only after he was assured that Google would not videotape or photograph the historic base, which serves as a medical-training and support post. The official had believed an online map would be useful to guide visitors.
"Unfortunately, Google didn't follow the rules," said the person, who requested anonymity because he was not authorized to discuss the situation.
Google spokesman Larry Yu said the driver in question broke Google's strict policy of not venturing onto military bases and private property.
"Against our policy, we did mistakenly access the base," Yu said.
Yu said Google would continue to work with Defense officials to ensure that sensitive imagery does not appear on Google Maps.
Rapidly evolving technology in a post-Sept. 11 world has created unforeseen national security challenges, defense analyst John Pike said. Street View's popularity has contributed to a growing number of services that incorporate street-level photos, including Berkeley-based Earthmine Inc. and EveryScape of Waltham, Mass.
"People know the rules have changed, but they don't know what the new rules are," Pike said. "All sorts of things are possible today that could not even be described 10 years ago."
Google Maps and another service called Google Earth have sparked concerns. Their aerial imagery displays a bird's-eye view of sensitive locations such as military bases, nuclear power plants and other potential terrorist targets that are ringed by fences and guards to keep the public out.
Last week, activists opposed to an expansion of London's Heathrow Airport said they plotted their stunt of protesting on the roof of the Houses of Parliament, in part, using images from Google Earth.
Google says the digital maps are part of its effort to organize the world's information, including visual data about the planet.
House-hunters can check out neighborhoods, tourists can locate landmarks and friends can pinpoint where to meet in an unfamiliar place just by entering addresses into Google Maps, then clicking the "Street View" button.
Google's version of "Candid Camera" raised the hackles of privacy advocates and incited spirited debate last year, when the company began dispatching a caravan of cars and trucks to snap close-up photographs of homes, shops and public places.
In the process they captured people, sometimes in indiscreet positions.
Within hours of its first release, bloggers spotted and posted photographs of students sunbathing in bikinis at Stanford University, motorists being ticketed by police, a man walking into an adult bookstore in Oakland and a man picking his nose on a San Jose park bench.