John Brennan made a reference to the protest that briefly disrupted his nomination hearing in asserting that many Americans have gotten the wrong idea about the administration's drone program.

Responding to a question from Sen. Ron Wyden (D-Oregon), he pushed back against the "misimpression" that drones strikes were carried out without proper oversight, for the purpose of "punishing terrorists for past transgressions."

"Nothing could be further from the truth," Brennan insisted. Referring to the protest by Code Pink activist that delayed the start of the confirmation hearing, he said: "The people standing up there have a misunderstanding ... of the care that we take to make sure we have no collateral damage or deaths."

But he later acknowledged that the administration still needs to explain more fully the conditions under which lethal force is authorized.

"The American people would be quite pleased to know that we have been very careful and very judicious," he said.