Underlining the paranoia prevalent in some quarters, a senior US air force general has claimed that Google's satellite mapping service, Google Earth , is a potential security risk and admitted that governments are already taking steps to counter this.

Lt. General David Deptula, who is deputy chief of staff for intelligence, surveillance and reconnaissance in the American air force, described the problems with giving open access to such imagery, saying, "It's something that was a closely guarded secret not that long ago and now everybody's got access to it."

Covering up

While acknowledging that the genie is already out of the bottle and isn't likely to be put back in, he admits that measures are already in place to conceal sensitive locations from the eye in the sky by using camouflage and other techniques.

Google Earth and its web-based counterpart, Google Maps , provide views of most of the Earth, ranging from long-range satellite shots to the recently added Street View, which uses cameras on the ground to provide imagery detailed enough to recognise people and see inside buildings.