The U.S. Senate Judiciary Committee is holding a hearing Tuesday on the president's wartime powers and the National Security Agency's surveillance authority.
The Republican chairman of that committee, Senator Arlen Specter of Pennsylvania has proposed a bill that would require the Department of Justice to get warrants every 45 days from a secret court to continue a controversial wiretapping program.
In December, The New York Times newspaper revealed that the Bush administration had authorized the NSA to monitor phone calls and e-mails between people in the U.S. and suspected terrorists overseas, without court approval.
On Monday, the newspaper sued the Department of Defense for failing to provide reporters with documents about the spying program.
Under the Freedom of Information Act, agencies of the Executive Branch of the U.S. government are required to disclose records upon receiving a written request, unless the documents meet certain exemptions.
The White House has defended the secret surveillance program, saying it is legal and necessary in the fight against terrorism.
Some information for this report was provided by AP and Reuters.