While US congressional committees are holding meetings to consider legislation by the Justice Department, organisations such as the Electronic Privacy Information Center (Epic) are urging Congress to be careful of changes that will affect privacy and constitutional rights.

Topics under consideration this week include electronic surveillance and intelligence gathering, which might chip away rights that safeguard all Americans, according to Epic.

Marc Rotenberg, Epic's executive director, said there is now a mix of provisions in the area of electronic surveillance that, if taken together, "would allow more people in government to monitor more electronic communications of Americans for more reasons under a lower legal standard than is currently permitted under law".

"This new statutory authority would be broadly exercised in cases completely unrelated to terrorism," he added.

Rotenberg said that police could now use Carnivore, a system that monitors web communication going in and out of an internet service provider's network, to routinely capture click-stream data from internet users under the same standards that currently permit government access to telephone numbers. Another provision will make it easier to seize voicemail.

"The vast majority of legislative recommendations now being faxed around Washington create sweeping surveillance authority without any justification," Rotenberg said.

The House Judicial Committee heard testimony from Attorney General John Ashcroft in which he told Congress that current US law is not adequate to protect American citizens from terrorist threats and that, in technology areas, the law is particularly out of date.

He said the FBI needed additional surveillance and enforcement powers immediately. "The American people do not have the luxury of unlimited time in erecting the necessary defences to future terrorist acts," Ashcroft said. "It requires that we provide law enforcement with the tools necessary to identify, dismantle, disrupt and punish terrorist organisations before they strike again."

Although many congressmen said they support the proposal, a number expressed concerns over potential violations of constitutional rights in the proposals.

US Senate Judiciary Committee chairman Patrick Leahy vowed to balance any new laws with the need to protect civil liberties. "If we let the Constitution get shredded, the terrorists win," he warned.

The American Civil Liberties Union said that several of Ashcroft's proposals were not objectionable, but it said many were excessive.