The leader of a House of Representatives panel has told Eric Holder, US attorney general, that they had serious concerns about the Justice Department's gathering of phone records at the Associated Press news agency.
Representative Bob Goodlatte, the Republican chairman of the House Judiciary Committee, said on Wednesday he worried about any infringement on freedom of the press in light of the Justice Department's actions in the investigation of national security leaks.
Representative John Conyers, a Democrat, said he was "troubled by the notion that our government would pursue a broad array of phone records over a period of time".
Holder is certain to face aggressive questioning by the Republican-led committee on topics ranging from the Justice Department's gathering of AP phone records to the government's handling of intelligence before the Boston Marathon bombings.
Goodlatte said he was concerned about the targeting of conservative groups by the US tax collecting agency, which is now the focus of an investigation by Holder's Justice department.
Media shield bill
Responding to news of the gathering of AP records, Senator Chuck Schumer, a Democrat, planned to revive a 2009 media shield bill that protects journalists and their employers from having to reveal information, including the identity of sources who had been promised confidentiality.
The law does contain some exceptions in instances of national security.
"This kind of law would balance national security needs against the public's right to the free flow of information," Schumer said in a statement. "At minimum, our bill would have ensured a fairer, more deliberate process in this case."
The White House threw its support behind the legislation, said a White House official, who was not authorized to speak on the record about the topic and demanded anonymity.
Ed Pagano, President Barack Obama's liaison to the Senate, placed a call on Wednesday morning to Schumer's office to ask him to revive the bill, a move the senator had planned to make.
Obama's support for the bill signified an effort by the White House to show action in the face of heated criticism from legislators from both parties and news organisations about his commitment to protecting civil liberties and freedom of the press.
White House officials have said they are unable to comment publicly on the incident at the heart of the controversy because the Justice Department's leak probe essentially amounts to a criminal investigation of administration officials.
Holder has said the collection of AP phone records stems from an investigation into national security leaks.
Republicans and some Democrats had pressed for an investigation last year, with many in Congress contending that the leaks were designed to enhance President Barack Obama's reputation in combatting terrorism as he sought reelection.
Holder on Tuesday defended the move to collect AP phone records in an effort to hunt down the sources of information for a May 7, 2012, AP story that disclosed details of a CIA operation in Yemen to stop an airliner bombing plot around the anniversary of the killing of Osama bin Laden.
The attorney general called the story the result of "a very serious leak, a very grave leak"..