Brennan speech is first Obama acknowledgement of use of armed drones "So let me say it as simply as I can," Brennan said in a speech at the Woodrow Wilson Center in Washington, D.C. "Yes, in full accordance with the law - and in order to prevent terrorist attacks on the United States and to save American lives -- the United States government conducts targeted strikes against specific al-Qaeda terrorists, sometimes using remotely piloted aircraft, often referred to publicly as drones." The White House's decision to acknowledge the use of drones, and the civilian casualties that have occurred during the strikes, comes on the anniversary of the death of al-Qaeda leader Osama bin Laden, at a time when the administration is moving to make its national security accomplishments a more central issue in the presidential campaign. Critics of the drone program described Brennan's speech as a critical step in opening a wider debate on a program that the White House had previously only referred to in glancing terms, including when Obama mentioned "these strikes" in an online chat with voters earlier this year. Brennan's speech "is an important statement, said Jameel Jaffer, deputy legal director at the American Civil Liberties Union, which has sued the government for greater disclosure about the use of drones. First because it includes an unambiguous acknowledgment of the targeted killing program and second because it includes the administration's clearest explanation thus far of the program's purported legal basis. Still, Brennan's speech was also noteworthy for how much was withheld. Brennan talked extensively about "targeted strikes against specific al-Qaeda terrorists," but did not acknowledge that the administration has also approved the use of so-called "signature strikes" in which the CIA and military have the authority to fire even in cases when the identities of those who could be killed is not known. Brennan did not provide details on the criteria by which targets are selected, the language of Justice Department legal opinions on the matter, and the numbers of strikes and casualties. Nor did he offer a comprehensive list of the locations where armed drone patrols occur. Instead, Brennan offered a broad outline and defense of a program that he described as critical to disrupting terrorist attacks and saving American lives, likening it to the use of a scalpel to remove cancerous tissue from a patient. Drones enable unprecedented "surgical precision," Brennan said, "the ability, with laser-like focus, to eliminate the cancerous tumor called an al-Qaeda terrorist while limiting damage to the tissue around it - that makes this counterterrorism tool so essential." Early in his remarks, Brennan was interrupted by a protester who shouted the names of U.S. citizens who have been killed in drone strikes in Yemen. Brennan was forced to pause for several minutes while woman was removed from the venue at the Woodrow Wilson Center. Brennan also signaled that further disclosures are forthcoming, saying that more files from the trove of material that was recovered from bin Laden's compound in Pakistan last year will be released online this week by an organization affiliated with the U.S. military academy at West Point.