Mexico has published rules governing the use of drones, allowing people to operate the smallest drones in daylight without a permit but with safety rules.

Mexico's Transportation Department has established three classes of drones according to size.

The smallest weigh 2 kilograms (4.4 pounds) or less. They won't require a permit, but like all other drones must stay 9.2 kilometers (5.72 miles) away from airports and 900 meters (985 yards) from helicopter pads.

Medium-size drones are defined as weighing between 2 kilograms and 25 kilograms (55 pounds), and require a permit unless they're operated on the grounds of a flight club.

Under rules published Wednesday, large drones over 25 kilograms will require an operating permit and the operator must also have a pilot's license.