WASHINGTON, March 10: US lawmakers, furious over reports that the FBI has repeatedly broken the law for obtaining private information about tens of thousands of people, threatened on Saturday to limit the agency’s anti-terror powers.

“We may have to rewrite that law and make it very tight,” said Senator Patrick Leahy, a Democrat who heads the Senate Judiciary Committee. “The FBI work for us, the American people, not the other way around,” said Mr Leahy while promising a hearing on the issue.

Senator Arlen Specter, the committee’s ranking Republican, also supported the move.

He said that it may be necessary to take back some of the vast authority FBI has been given since the Sept 11, 2001, terrorist attacks since they don’t “know how to use it”.

Senator Jon Kyl, an Arizona Republican who had voted for the act that gave FBI the authority to take such actions, said: “It shakes my confidence in the organisation which is given a very important power.”

The revelations about the misuse of power came in the first annual report to Congress on secret administrative subpoenas for wiretaps and searches related to national security.

The report accused the agency of collecting telephone and banking records, e-mail and other data under provisions of a law enacted to fight terrorism, the USA Patriot Act.

President George W. Bush, however, defended the FBI saying that the agency is addressing the problem and that he has full confidence in the bureau.

Civil liberties groups and some US lawmakers have strongly opposed surveillance methods allowed under the Patriot Act, saying that they violate fundamental rights and allow intrusion into the private matters of American citizens and legal residents.Inspector General Glenn Fine, who issued the report, said that the mistakes were the result of errors by agents, poor record-keeping and confusion about the process for properly getting access to the information.

The Patriot Act allows the FBI to issue the so-called “national security letters" to force businesses to hand over customer information. Companies that receive such letters aren’t allowed to tell anyone that a request for information has been made.

The inspector general’s report said that the FBI’s use of the letters violates the bureau’s own guidelines in many different ways.

The report said that tens of thousands of NSLs have been filed in the past few years ... and that more than ever are being used on US residents.