ASHINGTON, Nov. 30 — Attorney General John Ashcroft is considering a plan to relax restrictions on the F.B.I.'s spying on religious and political organizations in the United States, senior government officials said today.

The proposal would loosen one of the most fundamental restrictions on the conduct of the Federal Bureau of Investigation and would be another step by the Bush administration to modify civil-liberties protections as a means of defending the country against terrorists, the senior officials said.

The attorney general's surveillance guidelines were imposed on the F.B.I. in the 1970's after the death of J. Edgar Hoover and the disclosures that the F.B.I. had run a widespread domestic surveillance program, called Cointelpro, to monitor antiwar militants, the Ku Klux Klan, the Black Panthers and the Rev. Dr. Martin Luther King Jr., among others, while Mr. Hoover was director.

Since then, the guidelines have defined the F.B.I.'s operational conduct in investigations of domestic and overseas groups that operate in the United States.

Some officials who oppose the change said the rules had largely kept the F.B.I. out of politically motivated investigations, protecting the bureau from embarrassment and lawsuits. But others, including senior Justice Department officials, said the rules were outmoded and geared to obsolete investigative methods and had at times hobbled F.B.I. counterterrorism efforts.

Mr. Ashcroft and the F.B.I. director, Robert S. Mueller III, favor the change, the officials said. Most of the opposition comes from career officials at the F.B.I. and the Justice Department.

A Justice Department spokeswoman said today that no final decision had been reached on the revised guidelines.

"As part of the attorney general's reorganization," said Susan Dryden, the spokeswoman, "we are conducting a comprehensive review of all guidelines, policies and procedures. All of these are still under review."

An F.B.I. spokesman said the bureau's approach to terrorism was also under review.

"Director Mueller's view is that everything should be on the table for review," the spokesman, John Collingwood, said. "He is more than willing to embrace change when doing so makes us a more effective component. A healthy review process doesn't come at the expense of the historic protections inherent in our system."

The attorney general is free to revise the guidelines, but Justice Department officials said it was unclear how heavily they would be revised. There are two sets of guidelines, for domestic and foreign groups, and most of the discussion has centered on the largely classified rules for investigations of foreign groups.

The relaxation of the guidelines would follow administration measures to establish military tribunals to try foreigners accused of terrorism; to seek out and question 5,000 immigrants, most of them Muslims, who have entered the United States since January 2000; and to arrest more than 1,200 people, nearly all of whom are unconnected to the terrorist attacks of Sept. 11, and hold hundreds of them in jail.

Today, Mr. Ashcroft defended his initiatives in an impassioned speech to United States attorneys.

"Our efforts have been deliberate, they've been coordinated, they've been carefully crafted to not only protect America but to respect the Constitution and the rights enshrined therein," Mr. Ashcroft said.

"Still," he added, "there have been a few voices who have criticized. Some have sought to condemn us with faulty facts or without facts at all. Others have simply rushed to judgment, almost eagerly assuming the worst of their government before they've had a chance to understand it at its best."

Under the current surveillance guidelines, the F.B.I. cannot send undercover agents to investigate groups that gather at places like mosques or churches unless investigators first find probable cause, or evidence leading them to believe that someone in the group may have broken the law. Full investigations of this sort cannot take place without the attorney general's consent.

Since Sept. 11, investigators have said, Islamic militants have sometimes met at mosques — apparently knowing that the religious institutions are usually off limits to F.B.I. surveillance squads. Some officials are now saying they need broader authority to conduct surveillance of potential terrorists, no matter where they are.

Senior career F.B.I. officials complained that they had not been consulted about the proposed change — a criticism they have expressed about other Bush administration counterterrorism measures. When the Justice Department decided to use military tribunals to try accused terrorists, and to interview thousands of Muslim men in the United States, the officials said they were not consulted.

Justice Department officials noted that Mr. Mueller had endorsed the administration's proposals, adding that the complaints were largely from older F.B.I. officials who were resistant to change and unwilling to take the aggressive steps needed to root out terror in the United States. Other officials said the Justice Department had consulted with F.B.I. lawyers and some operational managers about the change.

But in a series of recent interviews, several senior career officials at the F.B.I. said it would be a serious mistake to weaken the guidelines, and they were upset that the department had not clearly described the proposed changes.

"People are furious right now — very, very angry," one of them said. "They just assume they know everything. When you don't consult with anybody, it sends the message that you assume you know everything. And they don't know everything."

Still, some complaints seem to stem from the F.B.I.'s shifting status under Mr. Ashcroft. Weakened by a series of problems that predated the Sept. 11 attacks, the F.B.I. has been forced to follow orders from the Justice Department — a change that many law enforcement experts thought was long overdue. In the past, the bureau leadership had far more independence and authority to make its own decisions.

Several senior officials are leaving the F.B.I., including Thomas J. Pickard, the deputy director. He was the senior official in charge of the investigation of the attacks and was among top F.B.I. officials who were opposed to another decision of the Bush administration, the public announcements of Oct. 12 and Oct. 29 that placed the country on the highest state of alert in response to vague but credible threats of a possible second terrorist attack. Mr. Pickard is said to have been opposed to publicizing threats that were too vague to provide any precautionary advice.

Many F.B.I. officials regard the administration's plan to establish military tribunals as an extreme step that diminishes the F.B.I.'s role because it creates a separate prosecutorial system run by the military.

"The only thing I have seen about the tribunals is what I have seen in the newspapers," a senior official complained.

Another official said many senior law enforcement officials shared his concern about the tribunals. "I believe in the rule of law, and I believe if we have a case to make against someone, we should make it in a federal courtroom in the United States," he said.

Several senior F.B.I. officials said the tribunal system should be reserved for senior Al Qaeda members apprehended by the military in Afghanistan or other foreign countries.

Few were involved in deliberations that led to the directive Mr. Ashcroft issued this month to interview immigrant men living legally in the United States. F.B.I. officials have complained that the interview plan was begun before its ramifications were fully understood.

"None of this was thought through, a senior official said. "They just announced it, and left it to others to figure out how to do it."

The arrests and detentions of more than 1,200 people since Sept. 11 have also aroused concerns at the F.B.I. Officials noted that the investigations had found no conspirators in the United States who aided the hijackers in the Sept. 11 attacks and only a handful of people who were considered Al Qaeda members.

"This came out of the White House, and Ashcroft's office," a senior official said. "There are tons of things coming out of there these days where there is absolutely no consultation with the bureau."

Some at the F.B.I. have been openly skeptical about claims that some of the 1,200 people arrested were Al Qaeda members and that the strategy of making widespread arrests had disrupted or thwarted planned attacks.

"It's just not the case," an official said. "We have 10 or 12 people we think are Al Qaeda people, and that's it. And for some of them, it's based only on conjecture and suspicion."