Washington ? The Justice Department is seeking to expand its anti-terrorism powers again, adding among other things an FBI subpoena power so secret that even a lawsuit challenging it had to be kept under wraps.

Experts say the changes, which are moving piecemeal through Congress in several bills, are among the most significant since Congress passed the Patriot Act in the frightening days after the Sept. 11, 2001, terror attacks.

Some of the measures being sought have been recycled from a controversial Justice Department draft of a bill, dubbed “Patriot II,” which was abandoned after details of its provisions leaked to the media.

Daniel Bryant, the assistant attorney general for legal policy, said the Patriot Act has helped law enforcement detect and disrupt terrorist plots.

“But while Congress and the administration working together have made significant strides in improving the department’s capacity to gather the intelligence necessary to prevent terrorist attacks, there is still more that needs to be done,” Bryant told lawmakers at a May 18 hearing.

Critics oppose giving law enforcement officials more power, complaining that not enough information has been made available about how the Justice Department is using the tools in the Patriot Act.

Lone-wolf provision

The Senate already has approved legislation making it easier for FBI agents to go after so-called lone-wolf terrorists not affiliated with any known organization or foreign government. The House of Representatives is considering the same measure as part of a larger bill dubbed the “The Anti-Terrorism Intelligence Tools Improvement Act of 2003.”

The provision would allow the government to conduct secret surveillance on suspected terrorists or spies without proving that they have any affiliation with a foreign government or terrorist organization. Critics worry that the government would use this change to snoop on people even if officials had no proof that they were part of a terror network.

The bill has two powerful co-sponsors, Rep. James Sensenbrenner, R-Wis., chairman of the Judiciary Committee, and Rep. Porter Goss, R-Fla., the chairman of the Intelligence Committee.

In addition to the lone-wolf provision, the bill would strengthen national security letters, which the FBI can use in counterterrorism or espionage cases to obtain business and financial records, as well as electronic communications from third parties, such as Internet service providers, medical offices or credit reporting agencies with no judicial oversight.

The legislation would punish someone who discloses that he or she has received a letter with up to five years in prison and allow the attorney general to seek a judge to enforce the letter if someone refuses to hand over the information the FBI wants.

Bryant said the gag order is critical because if people disclose that they received a national security letter, they could interrupt a sensitive terrorism investigation, possibly allowing the destruction of evidence and the flight of terrorism suspects.

He said the FBI has decided not to use national security letters in some cases out of fear that the person who received it would talk and compromise the investigation.

But how often the FBI has used national security letters — first authorized in 1986 — is unknown because the Justice Department has kept the figure classified. It’s widely believed, however, that their use is rising because the number of counterterrorism cases has skyrocketed.

Expanding death penalty

In addition to the Sensenbrenner-Goss bill, a separate bill is moving through the House Judiciary Committee, sponsored by Rep. John Carter, R-Texas, that would broaden the government’s ability to bring the death penalty The national security letter reforms, the lone-wolf terrorism provision and the death penalty enhancements were all in the draft of “Patriot II.”

The chief of the Justice Department’s criminal division, Christopher Wray, has also called for lawmakers to expand the material support law, which makes it a crime to provide financing, lodging, training or other assistance to terrorist organizations.

Rarely used prior to the Sept. 11 attacks, the material support law has become a favorite tool of federal prosecutors. Since the suicide hijackings, 58 people have been prosecuted for allegedly providing material support to al-Qaida or other terrorist groups.