Leak probe likely to include White House WASHINGTON (Reuters) - An investigation by two federal prosecutors into recent alleged leaks of classified information is likely to include scrutiny of White House officials, three people familiar with the probe said. The sources said that when Attorney General Eric Holder announced on Friday that the chief federal prosecutors in Washington and Maryland would pursue "all appropriate investigative leads within the executive and legislative branches of government," he signaled that examining the actions of White House officials would be within bounds. In an appearance on Tuesday before the Senate Judiciary Committee, Holder said: "Let me be very clear. Our investigation will follow leads wherever they take us. The U.S. Attorneys on the case, he said, have "the ability, they independence, they have the moxie." Holder, pushing back against Republican demands for an outside special counsel to investigate the national security leaks, said the two prosecutors would conduct a nonpartisan, independent investigation. One of the people familiar with the investigation said that because some of the media reports containing alleged leaks included information attributed to Obama administration officials, no investigation by the prosecutors "would be taken seriously if it didn't include" scrutiny of White House officials' actions. This individual and others requested anonymity because they weren't authorized to speak for the record. Holder, facing sharp questioning by senators, said that both he and FBI director Robert Mueller had already been interviewed by investigators about their knowledge of an intelligence operation targeting Al Qaeda in the Arabian Peninsula (AQAP), which some officials allege was disrupted as a result of leaks to the media. He also said that the two prosecutors involved in leak investigations would each be investigating "separate matters." While Holder declined to identify what these were, one avenue of inquiry is believed to be sensitive information about U.S. involvement in cyberwarfare against Iran's nuclear program, which was contained in a recent New York Times article. The other probe apparently involves the joint U.S.-British-Saudi operation against AQAP, al Qaeda's affiliate in Yemen. Last month, a prominent Republican Senator explicitly asked the FBI to investigate a possible leak related to the AQAP operation involving John Brennan, chief counter-terrorism advisor at the White House. In a letter to Mueller, Senate Intelligence Committee vice chairman Saxby Chambliss asked the FBI about a Reuters story last month which disclosed that a briefing by Brennan may have inadvertently tipped the media to sensitive information about an undercover informant who played a central role in the case. The FBI wrote back that it shared Chambliss' concerns and would investigate all leads, according to a source familiar with the matter. Still, it remains unclear how large a role Brennan's actions will play in the investigation into leaks regarding AQAP. The briefing by Brennan, came after an Associated Press report disclosed that U.S. counter-terrorism officials had disrupted a plot by the al Qaeda affiliate to plant an underwear bomber on a U.S. flight. In a subsequent conference call, Brennan told former counter-terrorism officials who appear as on-air TV analysts that the bomb plot was never a real threat because the U.S. had "inside control" over it. Within hours, one of the former officials who was on the call with Brennan speculated on the air that the U.S. "had somebody on the inside" of the plot. By the next day, news outlets were reporting that the U.S. had planted a double-agent inside al Qaeda affiliate. Because of the leaks, U.S. and allied officials said they were forced to prematurely end the operation. White House officials and some of the former officials who participated in the call with Brennan all said that he did not disclose classified information. Asked whether the White House had been contacted by the FBI or any other investigative authority in relation to leak inquiries, National Security Council spokesman Tommy Vietor said he had no comment beyond those on Friday in which President Barack Obama decried leaks. The Democratic president brushed off Republican allegations that some of the leaks appeared calculated to boost his re-election prospects, calling such charges "offensive." Chambliss joined a group of Republican senators led by John McCain and Lindsey Graham in sponsoring a Congressional resolution calling on Holder to replace the U.S. Attorneys he assigned to the leak investigations with an "outside special counsel" who could operate independently of Obama's Justice Department. Graham noted that a special counsel had been appointed in the case of Valerie Plame, a undercover CIA operative whose identity was disclosed to a journalist. That leak eventually led to criminal charges against a senior aide to Vice President Dick Cheney. Why wouldn't you need one here? Is this less serious? The allegations we are talking about here are breathtaking," Graham said. However, a Republican motion to have the Senate pass their resolution by "unanimous consent" failed when a Democrat, Senator Ron Wyden, objected. Dianne Feinstein, the Democrat who chairs the Senate Intelligence committee, said she also opposed the Republican plan, and defended the independence and scrupulousness of U.S. Attorneys Rod Rosenstein of Maryland and Ronald Machen of the District of Columbia, whom Holder assigned to the leak probes. Additional reporting by Susan Cornwell; Editing by Warren Strobel and Christopher Wilson