White House counterterrorism official John Brennan publicly described how Al Qaeda targets are chosen for drone strikes, the first time the Obama administration has described the widely known practice so openly and in such detail.

Brennan, speaking in Washington on Monday, says President Obama wants to be more transparent with the American public a year after a raid by Navy commandos killed Usama bin Laden in Abbottabad, Pakistan.

"Yes, 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," Brennan said.

Brennan's remarks amounted to both a defense and a public embrace of drone technology as the leading edge of the White House's clandestine war on terrorists from Yemen to Somalia.

Brennan says targets are chosen by weighing whether there is a way to capture the person against how much of a threat the person presents to Americans.

Targeting Al Qaeda members with lethal force by drones is legal, Brennan said, comparing it to targeting Japanese and German commanders in World War II.

He said use of drones was ethical because "only military objectives may be intentionally targeted and that civilians are protected from being intentionally targeted."

Brennan also called targeted strikes "wise," saying they kept both U.S. personnel out of harm's way, and that their precision munitions helped avoid civilian casualties caused by the kind of weapons dropped by jets.

He acknowledged, however, that civilian targets had been hit.

Brennan said in most cases, drone strikes are carried out with the cooperation of a host government.

Brennan's comments did not directly acknowledge the CIA's covert campaign in Pakistan, which has caused friction with the Pakistani government. Pakistan on Monday condemned a U.S. drone strike that killed three suspected Islamist militants in the northwest, the first since the country's parliament demanded that Washington end the attacks two weeks ago. In the past, Pakistan had publicly condemned strikes, but privately allowed them in specific geographic "boxes," namely in the tribal areas.

"We continue to believe, based on the information available, that the program itself is not just unlawful but dangerous," said Hina Shamsi, director of the American Civil Liberties Union's National Security Project. "It is dangerous to characterize the entire planet as a battlefield," Shamsi said.

A protester interrupted Brennan's remarks, shouting criticisms of the drone program. Her last words as she was dragged from the conference room by a security guard were "shame on you."