U.S. defence firm General Atomics expects the first sales of an unarmed export version of its Predator drone within months, seeing the Middle East and Latin America as particularly fertile markets.

So far, almost all of the more than 500 drones sold by the firm have gone to the U.S. military, a handful of other U.S. civilian government agencies, plus Britain, Italy and Turkey.

Other sales have been blocked by U.S. authorities under the terms of the Missile Technology Control Regime, an informal international agreement between states designed to limit the spread of sophisticated long-range weapons technology.

General Atomics Aeronautical director of international strategy development Christopher Ames said on Wednesday the sale of armed drones to anyone other than the closest U.S allies remained extremely unlikely.

But sales of the unarmed export Predator XP - specifically designed to be unable to carry lethal weaponry - were much more likely to be allowed and would soon start, he said.

“There has been very considerable international interest,” he told Reuters in an interview on the company’s stand at the Farnborough Airshow. “There have been countries that for a long time have been asking for Predator... (the export variant) opens up those markets to us.”

The San Diego-based privately owned company is one of the world’s leading suppliers of drones, but is facing mounting competition as other aerospace firms - both U.S. and foreign - bring their own systems to market.

While General Atomics was not in a position to announce any sales during the show itself, he said the first deals would likely be announced in the coming months if not sooner. The total number of drones sold would likely be in the dozens, he said.