Updated

With quadcopters and similar unmanned flying machines finding themselves in an increasing number of hobbyists' hands, it's little surprise that aerial-shot videos showing off iconic sites across the U.S. are appearing in ever greater number on sites like YouTube.

Indeed, recent reports out of San Francisco suggest drone operators have been unable to resist the lure of the city's grand Golden Gate Bridge, leading local officials to call for new powers to control flights (like the one above), citing safety and security concerns.

The issue was brought into sharp focus in recent days when one of the drones crashed onto the structure's roadway, though no one was injured in the incident.

Related: DT's review of the DJI Phantom 2 Vision+

Denis Muligan, the bridge's general manager, told a local news outlet that the remote-controlled copters have been spotted in off-limits locations such as behind security fences where photography is banned for security reasons.

Since 9/11, the bridge has been designated by Homeland Security as a "critical infrastructure" and as a result has undergone extensive work to improve its security.

As the law stands, there's little action the authorities can take against quadcopter operators flying their machines in restricted areas around the bridge, Muligan said.

So concerned are bridge officials about the drone flights that they've written to California Senator Dianne Feinstein to demand action.

"The increased pressence of these unmanned aircraft is a major threat, and is of significant concern to those charged with the security of the Golden Gate Bridge," the letter said.

Related: Zoom over yacht fires, Chernobyl, and volcanoes in the most amazing drone videos

While rules governing the commercial operation of drones remain strict, hobbyists still have a fair amount of freedom when it comes to using them, although a recent ban on flights in national parks could be a sign of things to come.

With drone ownership expanding at a rapid pace, it's likely that many more famous sites across the U.S. are experiencing the same challenges as those faced by the operators of the Golden Gate Bridge. The story of how the authorites control drone flights, both commercial and non-commercial, clearly has some way to run.