Two former US Air Force drone operators have come forward for the first time to denounce the country’s UAV program, saying it has aided the growth of the terrorist organisation ISIS.

Speaking at a press conference live streamed from New York, the two former drone pilots turned whistleblowers Stephen Lewis and Cian Westmoreland expressed deep concerns about the program and the impact it was having on people in the targeted regions.

“There’s always the off-chance that you could end up targeting someone that’s completely innocent, and that’s usually confirmed as an enemy kill,” said Westmoreland. “Those enemies aren’t always enemies. A military-aged male is 12 years old.”

They were joined by two other whistleblowers and former air force drone operators, Brandon Bryant and Michael Haas, who feature in the critically acclaimed documentary film Drone: The Documentary, which will have a theatrical release in New York, Los Angeles, Toronto and Montreal tomorrow.

Speaking during the press conference, Bryant said that for every four kills made by the drones, they create 10 terrorist members.

“They’re mostly tribal warrior culture. You arm these people and they’re going to want revenge,” he said.

Bryant argued that terrorists do use the fallout from drone strikes as a method to recruit. He spoke of how he had seen Youtube videos of burning drones and wondered whether current US policy was enabling ISIS to exploit its recruits.

The four whistleblowers also released details of an open letter sent to US President Barack Obama, US Secretary of Defence Ashton B Carter and CIA Director John Brennan.

In the letter they question whether the US’ military stance is fuelling the country’s perpetual state of war.

“Drones have changed warfare and our future, without us having a proper debate on what this means morally, ethically or legally,” said Drone: The Documentary director Tonje Hessen Schei. “The US is setting an extremely dangerous precedent with their use of drones, killing thousands of people outside of declared warzones.

“The US drone program is creating more militants than it kills. We are adding more fuel to the fire.”

“Amid an unprecedented crackdown on whistleblowers, these four operators are taking a tremendous risk,” added legal representative Jesselyn Radack.

“We’re the ultimate voyeurs, the ultimate peeping Toms – no one’s going to catch us,” said Bryant in the documentary. “And we’re getting orders to take these people’s lives. It was just point and click.”

Additional reporting by Daniel Davies