Washington ? The FBI, under sharp criticism for its peformance, will undergo a wholesale reorganization of its “structure, culture and mission” to better cope with threats against the United States in an age of terrorist attacks, Attorney General John Ashcroft said.

Both Ashcroft and FBI Director Robert Mueller publicly acknowledged bureau investigative lapses Wednesday and conceded the agency failed to quickly adapt to a changed law enforcement environment following the Sept. 11 attacks.

“It became clearer than ever that we had to fundamentally change,” Mueller said.

“Because our focus is on preventing terrorist attacks, more so than in the past we must be open to new ideas, to criticism from within and from without, and to admitting and learning from our mistakes,” he said.

The FBI director said the reorganization will make protecting the American people from another terrorist attack the FBI’s top priority. Number two, he said, will be protecting the United States against espionage. One change will require the bureau to hire some 900 new agents nationwide by September, mostly specialists in computers, foreign languages and sciences.

The broad reorganization will include a new office of intelligence and strengthened oversight of counterterror investigations. It also will improve FBI ties with the CIA and overhaul the FBI’s outdated computer systems.

Mueller pointedly criticized his bureau’s response to attempts by agents in the field to alert headquarters to the possibility before Sept. 11 that terrorists could hijack commercial aircraft and use them as weapons against the American people.

“Our analytical capacity is not where it should be,” he said, noting criticism the bureau has received from the legal counsel for the bureau’s Minneapolis field office for its handling of accused terrorist Zacarias Moussaoui, and its failure to respond sufficiently to a warning sounded by an agent in the Phoenix FBI office.

To prevent future terrorist attacks, Mueller said FBI headquarters will have to do a much better job of coordinating and analyzing information from its field offices, like the reports from Phoenix and Minneapolis.

“It is critically important that we have that connecting of dots that would enable us to prevent the next attack,” he said. “What we need to do better is being predictive… That is the shift.”

Ashcroft said the overhaul will occur “by shifting the FBI’s structure, culture and mission to one of preventing terrorism.”

“We have to do a much better job at recruiting, managing and training our work force,” Mueller said. “We have to do a better job of collaborating with others. We have to do a better job of collecting, analyzing and sharing information.”

Ashcroft expressed confidence in Mueller’s ability to see the agency through this historic transformation. “Bob Mueller is the right man for that job…. This reformer will overhaul the FBI,” he said. Mueller said he was grateful but said he found the attorney general’s praise “somewhat embarrassing.”

Other priorities for the reorganized FBI, Mueller said, will be preventing high technology crimes, combating public corruption, protecting the civil rights of Americans, battling national and international criminal organizations, combating major white collar crimes and violent crimes.

In advance of Wednesday’s announcement, Sen. Arlen Specter, R-Pa., had predicted that congressional hearings next week on the reorganization plan will focus on the bureau’s handling of the warning last June from its Phoenix office about an inordinate number of Arabs attending flight training schools in the United States.

The bureau also will have to answer questions about a letter from a Minnesota FBI agent angry about failed efforts to win permission to search the home and computer of Zacarias Moussaoui in the weeks before the Sept. 11 attacks. Moussaoui is awaiting trial on charges he was an accomplice in the September attacks.

“Before I can evaluate the adequacy of these changes, I have to know a lot more about the specifics of the problem,” said Specter, a member of the Senate Judiciary Committee. “It doesn’t do a lot of good to move names around on organization charts if there aren’t substantive changes. What’s going to happen to the next Phoenix memo? Where’s it going to end up?”

Although Mueller previously suggested a wholesale shift of some investigations to state and local police, officials say the FBI will continue to pursue bank robbers, white-collar criminals and drug dealers even as it concentrates more on terrorists.

The FBI has indicated it will increasingly ask state and local police for help on “note jobs,” bank robberies in which single armed bandits commit isolated thefts. The bureau also may seek local help with kidnappings when the victim is not taken across state lines.

State and local police convinced Mueller that a wholesale shift of some crimes away from the FBI was a bad idea. Some bank robberies, for example, are committed by thieves who are active interstate and might be stealing money for domestic terrorism. “The bureau needs to be in that circle,” said William Berger, president of the International Association of Chiefs of Police and the police chief in North Miami Beach, Fla.