All but the smallest civilian drones would have to broadcast radio tracking data to ensure greater safety and prevent terrorism under a sweeping proposal unveiled by U.S. regulators on Thursday.

The long-awaited draft rules call for a massive new tracking network for everything from toys to larger commercial drones so that law enforcement can spot the devices flying anywhere, from congested urban areas to the most rural zones.

The controversial measure by the Federal Aviation Administration, which is subject to public comment and could change before it becomes final, is a key foundation to advance drone-driven commerce, including deliveries of consumer goods by companies such as Alphabet Inc.'s Wing and Amazon's Prime Air. The rules would come into full force three years after being finalized.