ASHINGTON, Dec. 11 ó Concerned about how federal access to their records would undermine readers' privacy, thousands of librarians gathered today around the country to hear televised advice about how to respond to government requests under last year's antiterrorism law.

Although some of the librarians calling in from among the 250 sites in a national teleconference suggested defiance of the 2001 USA Patriot Act, all the speakers said proper federal requests for data should be dutifully complied with, but only when a proper court order was served and not just because an F.B.I. agent asked for information.

But they offered one consistent piece of advice: the fewer records that were kept, the less information the government could see. Even necessary records should be promptly destroyed after use, they said.

Gary E. Strong, director of the Queens Borough Public Library in New York, said that the act did not require additional record keeping but that when federal authorities sought records under its provisions, "if you have records, you must make them available."

James Neal, the librarian for Columbia University, said: "There is nothing in the law which requires us to authenticate any individuals as they act to use collections or electronic information. There is nothing which dictates what information we need to collect."

Almost all states have laws keeping the details of library use secret except for clear law enforcement needs. But Thomas M. Susman, a lawyer here who deals with library issues, warned the librarians not to count on state laws for protection. Federal law, he said, "trumps" such protections.

Librarians have been concerned over reader privacy since the anti-terrorism law was passed, despite their lobbying against the provisions affecting libraries. But they have found it hard to quantify the problem because orders obtained under the law come with a judicial directive that bars disclosure of the order to the news media or the public.

The Justice Department has refused to make public how often it has used its new powers and is being sued for the information by the American Library Association, the American Civil Liberties Union and the Electronic Privacy Information Center.

A survey conducted late last year by the Library Research Center of the University of Illinois, indicated that 4.1 percent of all libraries, and 11.4 percent of those in communities of 50,000 people or more, had been asked about their patrons by either the Federal Bureau of Investigation or the police.

Leigh Estabrook, dean of the the university's School of Library Science, said she thought those percentages were probably low. "Librarians are fairly cautious," Ms. Estabrook, said.

Judith F. Krug, director of the American Library Association's Office for Intellectual Freedom, said last summer that the issue was hardly new, for the F.B.I. had conducted such surveillance programs in the past. "We believe that what you read is nobody's business but your own," Ms. Krug continued. "If you convert what you read into illegal behavior, then there are laws to deal with that. But just because someone reads how to build a bomb doesn't mean you're a bomber. There is no way you can tell."

None of the speakers at today's conference, sponsored by five library associations, said that government access to library records was being abused. "We may not feel comfortable," Mr. Susman said, "but as yet we have no foundation for inferring guilt."

But the speakers urged librarians to keep careful notes on the law's use.

Tracy Mitrano, who directs computer policy at Cornell University, said, "We can begin to create a record to see if there is abuse."

She added, "Of course we want to work in whatever ways we can to fight terrorism, but if another drop of blood is not shed, we will still have lost that war against terrorism if we forsake our constitutional liberties."

Mr. Susman, a former aide to Senator Edward M. Kennedy, Democrat of Massachusetts, said he was accustomed to being called a liberal but was not sure where he would stand in librarians' opinion.

"Just as opposing government intrusions on private lives is not unpatriotic," he said "support for effective law enforcement and enhanced security isn't necessarily a sign of being right wing or reactionary."