WASHINGTON – Uncomfortable with the Obama administration's use of deadly drones, a growing number in Congress is looking to limit America's authority to kill suspected terrorists, even U.S. citizens. The Democratic-led outcry was emboldened by the revelation in a newly surfaced Justice Department memo that shows drones can strike against a wider range of threats, with less evidence, than previously believed.

The drone program, which has been used from Pakistan across the Middle East and into North Africa to find and kill an unknown number of suspected terrorists, is expected to be a top topic of debate when the Senate Intelligence Committee grills John Brennan, the White House's pick for CIA chief, at a hearing Thursday.

The White House on Tuesday defended its lethal drone program by citing the very laws that some in Congress once believed were appropriate in the years immediately after the Sept. 11 attacks but now think may be too broad.