President Obama has ordered the US Justice Department review the policy under which it obtains journalists' records.
The move comes after the administration was criticised for secretly seizing two months of phone records from The Associated Press and reading the e-mail of a Fox News reporter as part of separate investigations about the publication of government secrets.
Obama re-stated his support for a media shield law that he said would "guard against government overreach." Such a law would require a federal judge to sign off before officials could access the records of journalists. Mr Obama said:
Journalists should not be at legal risk for doing their jobs. Our focus must be on those who break the law.