NEW YORK (AP) — Amazon is giving new details on its Prime Air drone delivery program. But the timeline is still unclear.

The retailer says Prime Air will one day deliver packages up to 5 pounds in 30 minutes or less using small drones.

The drones will fly under 400 feet and weigh less than 55 pounds, according to details posted on its website Sunday. It says it will use technology and automation to operate safely.

Seattle-based Amazon.com Inc. said Monday the program will start once government regulations are in place to support it. It has development centers in the U.S., the U.K. and Israel.

The FAA currently bans commercial drone flights except for a few dozen companies that have been granted waivers. It has granted Amazon approval to fly drones for research.