US aviation authorities are allowed to pursue small drone operators suspected of operating their radio-controlled devices in a reckless manner, a US government agency ruled Tuesday.

The decision by the National Transportation Safety Board (NTSB) is the latest chapter in an ongoing legal battle between a Swiss drone entrepreneur based in Hong Kong and the Federal Aviation Administration (FAA).

An NTSB administrative law judge in March dismissed a $10,000 fine that the FAA had imposed on Raphael Pirker for using a Ritewing Zephyr drone to shoot a promotional video for the University of Virginia.

The FAA -- which held that Pirker flew his drone in a reckless manner, in violation of federal air regulations -- promptly appealed that decision to the full NTSB panel.

In a brief statement Tuesday, that NTSB panel said the ban on careless or reckless flying extended to small drones, not just conventional aircraft, and that the FAA could enforce it.

The panel sent the determination of whether Pirker had flown his drone in a reckless manner back to a judge. Pirker currently runs a drone business in Hong Kong.

"An administrative law judge would need to review evidence showing the operation was careless or reckless," said the NTSB, which acts as a court of appeal for FAA enforcement actions.

The FAA all but bans the unauthorized use of drones for commercial purposes in the United States -- a limitation that critics say is stifling the development of drone technology.

Pirker's lawyer Brendan Schulman disagreed with the decision, but said it was "narrowly limited" to the question of whether drones were subject to the ban on reckless flying.

"The more significant question of whether the safe operation of drones for business purposes is prohibited by any law was not addressed in the decision," he told AFP by email.

Schulman said he is still considering the next step in the Pirker case.

The Ritewing Zephyr drone that Pirker used to make the University of Virginia video is made of Styrofoam and weighs about five pounds (2.26 kilograms).

The FAA said in a statement its $10,000 fine on Pirker "should stand" and that it looked forward to proving "the 'careless or reckless' nature of the operation in question."

Pirker's company in Hong Kong, Team BlackSheep, sells small drones to around 80 countries for aerial videos, agriculture, property inspection and recreational use.