SEATTLE/WASHINGTON, March 14 (Reuters) - U.S. Transportation Secretary Sean Duffy said on Friday that the Federal Aviation Administration plans to propose rules to expand use of drones for deliveries and other services.

"We're in the stages of developing a rule to make sure we can give more authority and clarity to those who are developing these drones," Duffy told reporters after a tour of Amazon Prime Air drone delivery service's headquarters in Seattle, saying the agency plans to release a proposal "in relatively short order."

Last month, the Commercial Drone Alliance urged President Donald Trump's administration to release a proposed rule that would allow commercial unmanned aircraft systems or drone operations beyond visual line of sight, saying the rule "is essential to enable this industry to succeed."

The rule would "normalize commercial drone operations that are otherwise prohibited or require individual approval through bureaucratic and time-consuming FAA application processes."

The FAA has done substantial work to prepare the draft rule and other federal agencies have provided input, the group noted.

Drone delivery companies have raised concerns that the U.S. could fall behind China.

"If we don't have clear rules that allow innovators to innovate and create products and test products, it won't happen here," Duffy said. "It's going to happen somewhere else, and then we'll import someone else's technology into this country to develop whether it is in packages or groceries."

In January, the Commerce Department under former President Joe Biden said it was considering rules to restrict or ban Chinese drones in the U.S., citing national security concerns.

China accounts for the vast majority of U.S. commercial drone sales. Washington has increasingly cracked down on Chinese drones over the last year.

In December, Biden signed legislation that could eventually ban China-based DJI and Autel Robotics from selling new drone models in the U.S. (Reporting by Dan Catchpole in Seattle and David Shepardson in Washington; Editing by David Gregorio)