The FBI says it is working on a request for information about its controversial Carnivore e-mail snooping system, and should begin turning over some data within 45 days.

But the privacy group that made the request called the announcement "virtually meaningless."

The FBI filed a written status report Wednesday at the U.S. District Court in Washington, saying it is reviewing internal documents about Carnivore and should begin releasing cleared information in about 45 days, with future releases every 45 days.

The report did not say what or how much information will be released in each interval, or whether it will include the surveillance tool's source code. The source code is considered key to understanding how the system operates.

"I think this is far too vague to really comply with their legal obligations," said David Sobel, general counsel for the Electronic Privacy Information Center, which filed a Freedom of Information Act request last month for the information.

"They need to make a commitment to process 'X' number of documents every 45 days or else this schedule is virtually meaningless," he said, adding that his center likely will now ask the judge in the case to impose more detailed terms upon the FBI's schedule.

The FBI and Justice Department lawyers said in the filing to Judge James Robertson that some of the material may contain classified information.

Attorney General Janet Reno said it would take time to determine what can be released publicly. "There's some 3,000 pages that we have got to go through, and we want to do it as expeditiously as possible but we want to do it properly," she said Thursday at her weekly news conference.