It was hardly a secret, but the Obama Administration is offering more details than ever before about the use of drones to kill terrorists.

FOX News Radio's Jared Halpern has more from Washington DC as part of our ongoing series on national security:

Securing America.

In a candid speech to a Washington think tank:

Brennan: "So let me say it as simply as I can."

White House Counterterrorism Chief John Brennan says the U.S. does regularly use unmanned, armed drones to target al-Qaeda leadership.

Brennan: "Targeted strikes conform to the principle of necessity. The requirement that the target have definite military value."

Brennan defending the use of drone strikes as legal and ethical. They have proved controversial; linked to the killing of American Cleric Anwar al-Awlaki and his son in Yemen.

In Washington, Jared Halpern, FOX News Radio.