Wracked by a string of failures, the FBI is getting overhauled to strengthen the bureau's ability to fight terrorism.

FBI Director Robert Mueller announced Monday that his plan will create four branches within the bureau that will report directly to him -- one to deal with criminal investigations, one to deal with counter-terrorism and counter-intelligence operations, and two to deal with in-house operations.

Mueller's plan doesn't call for an immediate replacement for the position of Deputy Director -- the number two spot at the FBI. Instead, four Executive Assistant Directors will head the branches. Deputy Director Tom Pickard retired from the FBI last month, leaving his post vacant. Mueller said he may eventually fill the spot, but he's in no rush.

"I don't intend to fill it in the immediate future," Mueller said.

The four new Executive Assistant Directors will be:

— Criminal Investigations: Ruben Garcia, to oversee cyber-crime investigations and other major criminal cases;

— Counter-terrorism and Counter-Intelligence: Dale Watson, whose duties will include oversight of a new Office of Intelligence, which doesn't have a director yet;

— Law Enforcement Services: Kathleen McChesney, who will oversee the FBI's lab, the Critical Incident Response Group, training of all agents and a new Law Enforcement Coordination Unit to work specifically with state and local law enforcement agencies; and

— Administration: Bob Chiaradio, who will oversee finances, information resources and two areas that have come under fire in the wake of FBI blunders in the Robert Hanssen spy and Tim McVeigh documents case — internal security and recordkeeping.

Many of the employees to staff the criminal and counter-terrorism units will come from the investigative services division, a branch of the bureau formed two years ago under Mueller's predecessor, Louis Freeh. Freeh's move was part of a restructuring to shore up the bureau's ability to identify and prevent terrorism and other crimes, rather than investigating crimes or attacks after they have occurred. Agents complained it left the other divisions short-staffed.

Mueller said he was pulling the analysts from investigative services and other departments in order to have them work on cases directly, rather than be segregated into a separate unit.

Mueller said the reorganization, which was approved by Congress last week and is effective immediately, only affects operations at headquarters, and will not directly affect either the investigation into the Sept. 11 terrorist attacks or the anthrax investigation.

Reaction from Congress was mixed.

"Less than three months after taking office and in the midst of the greatest terrorist challenge the FBI has ever faced, Director Mueller has devised a dynamic plan to put the Bureau back on the right track," said Sen. Patrick Leahy, D-Vt., chairman of the Senate Judiciary Committee.

"Reorganization plans come and go. And new charts and graphs about who is in charge of what won't correct a management culture that's focused on headlines over the nuts and bolts of investigative work. So this new plan warrants even more oversight from Congress. We need to make sure changes are real, and that old FBI offices and functions aren't simply being re-adorned with new names and descriptions," said Sen. Charles Grassley, R-Iowa.

Mueller's announcement comes after a series of shifts within the Justice Department. The FBI, a division of the Justice Department, has moved resources to focus on investigating and disrupting additional terrorist attacks, though agents continue to investigate the Sept. 11 attacks and anthrax cases.

Last month, Attorney General John Ashcroft announced that 10 percent of the resources and jobs within the Justice Department would be moved out of the nation's capital to field offices, and more FBI agents, immigration screeners and prosecutors would be added to the payroll.

The goal, he said, is to shift the FBI's focus toward preventing terrorist acts from its previous role of solving traditional crimes. Local police will continue that task.

"We cannot do everything we once did because lives now depend on us doing a few things very well," the Ashcroft said.

Mueller said a second, more ambitious phase to restructure the FBI's mission and resources will likely be unveiled early next year. That plan involves a look at where agents are deployed, moving more agents out of headquarters and into field offices, and putting more agents on counter-terrorism and cyber-crime investigations.

Mueller said the FBI will take a close look at some investigations and may decide that other agencies or local law enforcement officers might be better equipped to handle some crimes, like bank robbery or smaller drug operations.

The FBI reorganization was underway long before the Sept. 11 attacks, and even before Mueller took over this summer. The bureau had been criticized for its handling of the Wen Ho Lee nuclear thefts case, paperwork blunders that led to a one-month delay in the execution of convicted Oklahoma City bomber Timothy McVeigh, and the failure to detect the fact that FBI agent Robert Hanssen was spying for Russia.

Former FBI and CIA Director William Webster is conducting one of several reviews of FBI procedures, and some of his recommendations were incorporated into the changes Mueller announced Monday.

The Associated Press contributed to this report.