Amazon's plans to launch a fleet of delivery drones has been dealt a blow by a draft ruling from the US Federal Aviation Authority (FAA), Digital Spy reports.

The legislation proposes that unmanned aircraft should not be able to drop off cargo packages or operate after sunset.

Furthermore, the FAA has ruled that pilots operating an unmanned aircraft must keep the drone within eyeshot at all times.

Amazon's Prime Air drones are a fleet of octocopters designed to carry packages weighing up to 20kg to customers in record time.

US air regulations have prevented the retailer from testing the hardware domestically, but Amazon remains committed to the project and is prepared to trial it overseas in countries such as India.

"We are committed to realising our vision... and are prepared to deploy where we have the regulatory support we need," said Paul Misener, Amazon's vice-president of global public policy.

The FAA's latest ruling is still in the proposal stage and must pass through public consultation before becoming law.