WASHINGTON, March 22: The Bush administration is involved in a new political storm following revelations that State Department contractors had improperly reviewed private passport files of three leading presidential candidates, Barack Obama, Hillary Clinton and John McCain.The scandal may further hurt the incumbent Republicans in an election year.

The news of prying into Mr Obama’s file came on Thursday evening and on Friday, Secretary of State Condoleezza Rice publicly apologised to Senator Obama and revealed that Mrs Clinton’s passport file was also breached in 2007 but gave no details.

The State Department said later Friday that the same contract employee who examined Senator Obama’s file also looked at Senator McCain’s.

In a Friday press conference about the Obama file incident, Ms Rice said there would be “a full investigation” and told reporters she called Mr Obama and told him “I was sorry and that I myself would be very disturbed if I learned somebody had looked into my passport file and therefore I will stay on top of it”.

Two of the contract employees were fired for the security breach and a third was disciplined but is still working, the State Department said. None of the employees have been identified.

House Oversight and Government Reform Committee Chairman Henry Waxman, meanwhile, sent a letter to Ms Rice asking for names by Monday. “I am writing to request that you provide the Oversight Committee by Monday with the identities of the companies involved in these breaches,” the letter said. “I also believe this information should be made publicly available.”

Senator Joseph Biden, chairman of the Senate Foreign Relations Committee, demanded an inquiry.

“Firing or disciplining those responsible is an important first step. But we need to understand why these employees had access to this information in the first place, why they sought the information, and why it took over two months for this matter to come to light,” he said.

Ms Rice said the State Department will share its information with Mr Obama and said the breach should have been known to senior officials. But “it was not to my knowledge”, she added.

Senior management at the State Department learned that the three workers at three locations accessed Mr Obama’s information on Jan 9, Feb 21 and March 14. Mr Obama’s campaign called the breach “outrageous” and demanded to know “who looked at Senator Obama’s passport file, for what purpose, and why it took so long for them to reveal this security breach”.