WASHINGTON – The FBI secretly sought information last year on 3,501 U.S. citizens and legal residents from their banks and credit card, telephone and Internet companies without a court’s approval, the Justice Department said Friday.

It was the first time the Bush administration has publicly disclosed how often it uses the administrative subpoena known as a National Security Letter, which allows the executive branch of government to obtain records about people in terrorism and espionage investigations without a judge’s approval or a grand jury subpoena.

Friday’s disclosure was mandated as part of the renewal of the Patriot Act, the administration’s sweeping anti-terror law.

The FBI delivered a total of 9,254 security letters relating to 3,501 people in 2005, according to a report submitted late Friday to Democratic and Republican leaders in the House and Senate. In some cases, the bureau demanded information about one person from several companies.

The numbers from previous years remain classified, officials said.

The department also reported that it received a secret court’s approval for 155 warrants to examine business records last year under a Patriot Act provision that includes library records. However, Attorney General Alberto Gonzales has said the department has never used the provision to ask for library records.

The number was a significant jump over past use of the warrant for business records. A year ago, Gonzales told Congress there had been 35 warrants approved between November 2003 and April 2005.

The spike is expected to be temporary, however, because the Patriot Act renewal that President Bush signed in March made it easier for authorities to obtain subscriber information on telephone numbers captured through certain wiretaps.

The Foreign Intelligence Surveillance Court, the same panel that approves applications for warrants on business records, also approved 2,072 special warrants last year for secret wiretaps and searches of suspected terrorists and spies.

Ann Beeson, the associate legal counsel for the American Civil Liberties Union, said the report “confirms our fear all along that National Security Letters are being used to get the records of thousands of innocent Americans without court approval.”