WASHINGTON — State Department workers viewed passport applications containing personal information about high-profile Americans, including the late Playboy playmate Anna Nicole Smith, at least 20 times since January 2007, The Associated Press has learned.

That total is far more than disclosed last week with the news that presidential candidates Hillary Rodham Clinton, John McCain and Barack Obama had been victims of improper snooping.

An internal department review has found the additional instances of department employees or contractors looking at computerized passport files of politicians and celebrities, according to preliminary results.

It has not been determined if the new cases also involved improper peeking, officials familiar with the review said Wednesday. Smith's case, however, seems legitimate, the officials said. The review is not complete and the exact number of cases was not yet clear.

They spoke on condition of anonymity because the review is going on at the same time as the department's own watchdog investigates passport record security related to the breaches involving the White House candidates.

Smith, 39, died in February 2007 death from an accidental overdose in Florida and was buried in the Bahamas, where she had moved in 2006. The review of her passport file appears to have come after a legitimate request from the U.S. Embassy in the Bahamas for information needed to complete her death certificate, the officials said.

Supervisors recorded each instance a file was viewed because the applications in question belonged to members of a select group of several hundred citizens whose passport files were "flagged" for extra protection due to their visibility, the officials said. Among these people are government leaders, movie stars and athletes, the officials said.

The list maintained by Bureau of Consular Affairs has included as many as 500 people at any one time, they said. The list is kept secret partly to deter workers from making unauthorized inquiries into high-profile records. Although there are no formal criteria for inclusion, people on the list are deemed to warrant special consideration because of their public status, the officials said.

The investigation begun by the department's inspector general after last week's disclosure covers some of the same ground as the internal review but also will examine whether the searches of the candidates' records were politically motivated. Thus far, officials say they believe that snooping resulted from "imprudent curiosity."

Two contractors were fired and a third disciplined for breaching Obama's records three times and McCain's records once. A department employee who looked at Clinton's file as part of a training exercise was reprimanded.

The companies that provided the contractors _ Stanley Inc., of Arlington, Va., and The Analysis Corp., or TAC, of McLean, Va. _ have said their employees' actions were unauthorized and not consistent with company policies.

Accessing any of the flagged files triggers an automatic notification that the record has been viewed. That allows supervisors to check whether it was done for a legitimate reason, such as an official request for verification of information contained in an actual passport.

The review being conducted by Patrick Kennedy, undersecretary of state for management, is expected to result in increased security measures for the passport files of flagged individuals, the officials said.

The most likely step would mean special security for those records, making them accessible to passport employees only after they get permission to view them from a supervisor, the officials said.

That restriction now applies to the files of the three candidates. Kennedy hopes to have it cover all high-profile records before the inspector general's report is completed and ahead of congressional hearings on passport security, the officials said.

In addition, Kennedy wants to expand the list to more than 500 individuals, they said.

But that is unlikely to pre-empt calls for a separate Justice Department investigation into whether the breaches of the candidates' files violated federal laws. Nor would it address concerns that the files of millions of people not considered high-profile enough for the extra protection may also have been improperly accessed.

It is unclear what the contractors might have seen in the candidates' records. Passport applications typically contain only basic personal information such as name, citizenship, age, Social Security number and place of birth. The files generally would not list countries the person has traveled to.

But Passport Services maintain other records that can include information such as marriages overseas, court orders, arrest warrants and medical and financial reports. Further, outside "users" _ including other government agencies and foreign governments _ may be given certain information.

But the department says extraneous information would be included in passport application files only under rare circumstances, such as suspected fraud. Also, foreign governments are not given access to the U.S. electronic system that contains the files, it said.

(This version CORRECTS that Smith died in Florida, was buried in the Bahamas, where she had moved in 2006)