WASHINGTON- A regular US air force unit based in the Nevada desert is responsible for flying the CIA's drone strike programme in Pakistan, according to a new documentary to be released on Tuesday.

The film – which has been three years in the making – identifies the unit conducting CIA strikes in Pakistan's tribal areas as the 17th Reconnaissance Squadron, which operates from a secure compound in a corner of Creech air force base, 45 miles from Las Vegas in the Mojave desert. Several former drone operators have claimed that the unit's conventional air force personnel – rather than civilian contractors – have been flying the CIA's heavily armed Predator missions in Pakistan, a 10-year campaign which according to some estimates has killed more than 2,400 people. Hina Shamsi, director of the American Civil Liberties Union's National Security Project, said this posed questions of legality and oversight. "A lethal force apparatus in which the CIA and regular military collaborate as they are reportedly doing risks upending the checks and balances that restrict where and when lethal force is used, and thwart democratic accountability, which cannot take place in secrecy."

The Guardian approached the National Security Council, the CIA and the Pentagon for comment last week. The NSC and CIA declined to comment, while the Pentagon did not respond. The role of the squadron, and the use of its regular air force personnel in the CIA's targeted killing programme, first emerged during interviews with two former special forces drone operators for a new documentary film, Drone.

Brandon Bryant, a former US Predator operator, told the film he decided to speak out after senior officials in the Obama administration gave a briefing last year in which they said they wanted to "transfer" control of the CIA's secret drones programme to the military. Bryant said this was disingenuous because it was widely known in military circles that the US air force was already involved. "There is a lie hidden within that truth. And the lie is that it's always been the air force that has flown those missions. The CIA might be the customer but the air force has always flown it. A CIA label is just an excuse to not have to give up any information. That is all it has ever been."

Bryant said public scrutiny of the programme had focused so far on the CIA rather than the military, and it was time to acknowledge the role of those who had been carrying out missions on behalf of the agency's civilian analysts. "Everyone talks about CIA over Pakistan, CIA double-tap, CIA over Yemen, CIA over Somalia. But I don't believe that they deserve the entirety of all that credit for the drone programme," he said. "They might drive the missions;they might say that these are the objectives – accomplish it. They don't fly
it."

Shamsi said the revelations, if true, raised "a host of additional pressing questions about the legal framework under which the targeted killing programme is carried out and the basis for the secrecy that continues to shroud it." She added: "It will come as a surprise to most Americans if the CIA is directing the military to carry out warlike activities. The agency should be collecting and analysing foreign intelligence, not presiding over a massive killing apparatus.