WASHINGTON — A growing number in Congress is looking to limit US authority to kill suspected terrorists, including American citizens. The Democratic-led outcry at the Obama administration's use of deadly drones 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, 2001 attacks but now think may be too broad. "It has to be in the agenda of this Congress to reconsider the scope of action of drones and use of deadly force by the United States around the world because the original authorization of use of force, I think, is being strained to its limits," Democratic Sen. Chris Coons said in a recent interview. Congressman Steny Hoyer, the No. 2 Democrat in the House of Representatives, said Tuesday that "it deserves a serious look at how we make the decisions in government to take out, kill, eliminate, whatever word you want to use, not just American citizens but other citizens as well." Hoyer added: "We ought to carefully review our policies as a country." The Senate Foreign Relations Committee likely will hold hearings on US drone policy, an aide said Tuesday, and Democratic Chairman Robert Menendez and the panel's top Re publican, Sen. Bob Corker, both have quietly expressed concerns about the deadly operations. Both the CIA and the US military are authorized to remotely pilot unmanned, missile-carrying drones against terror suspects. It's unknown exactly how many strikes have been carried out, but experts say that drone attacks in Pakistan are conducted by the CIA, while those in Yemen and Somalia, for example, are by military forces. The drones have strained diplomacy between the US and the nations where the strikes are carried out, as civilians have been killed alongside the targeted terrorists, even though most nations have given Washington at least tacit agreement to carry out the attacks. A Middle Eastern diplomat said that in Yemen, for example, an uptick of US drone strikes last month have killed dozens of people and upset the local public, leading some leaders in Sanaa to reconsider how often they should be used. The diplomat spoke Tuesday on condition of anonymity to avoid political retribution from the Obama administration. The Pentagon is also considering basing surveillance drones in Niger to monitor on burgeoning extremist violence in North Africa, but it's not clear if they will be armed. Brennan, who currently serves as the White House counterterrorism czar, has signaled he is prepared to turn the CIA from carrying out lethal drone strikes and hand over those missions to the US military. Sen. Ron Wyden, a senior Democratic member of the Senate Intelligence panel, declared himself unsatisfied Tuesday with the Justice memo and said he will press Brennan at the confirmation hearing about the administration's current policy. — AP