Washington's increasing use of unmanned drones to kill people in developing countries looks set to remain shrouded in secrecy after a US federal judge dismissed a lawsuit on Friday that aimed to force the Obama administration to divulge official information.
The CIA rejected a Freedom of Information Act request from the American Civil Liberties Union (ACLU).
The spy agency refused to admit or deny that it had any relevant records and said that merely confirming the existence of material would reveal classified information.
US District Judge Rosemary Collyer rejected the ACLU's argument that former CIA director Leon Panetta had officially acknowledged the agency's use of drones.
In arguing for disclosure the ACLU cited Mr Panetta's answer after a 2009 speech to a question from an audience member who said President Barack Obama's strategy in Pakistan was "drone strikes."
Without using the two words himself Mr Panetta responded: "It does suffice to say that these operations have been very effective."
But the judge ruled that "these comments did not officially disclose the CIA's involvement in the drone-strike programme."
Filing the freedom of information request in 2010 ACLU activist Jameel Jaffer said: "The use of drones to conduct targeted killings raises complicated questions - not just legal questions but policy and moral questions as well.
"These are not questions that should be decided behind closed doors. They are questions that should be debated openly and the public should have access to information that would allow it to participate meaningfully."
Some 168 children have been killed in seven years of CIA drone strikes in Pakistan's tribal areas alone, according to the Britain-based Bureau for Investigative Journalism.