U.S. presidential hopefuls Barack Obama, Hillary Clinton and John McCain have all had their passport files breached, the U.S. State Department confirmed Friday.

The State Department said Thursday that Obama's files had been looked at by employees within the department. However, the department only discovered Friday that files belonging to Clinton and McCain had also been breached.

Speaking from Paris, Sen. McCain said he wants a full investigation. "The United States of America values everyone's privacy and corrective action should be taken," he said.

State Department spokesman Sean McCormack said there will be a probe into all of the breaches. It will be monitored by the Justice Department and will also look at the larger security issues involved.

McCormack said investigators are "also going to take a look at whether there are any systemic issues that need to be addressed."

Clinton said in a statement Friday that U.S. Secretary of State Condoleezza Rice contacted her and told her of the breach of her records, which occurred in 2007.

Rice had also phoned Obama -- Clinton's rival for the Democratic leadership -- about his case.

"I told him that I was sorry, and I told him that I myself would be very disturbed," said Rice.

"None of us wants to have a circumstance where any American's passport files are looked at in an unauthorized way," she said.

Two contractors were fired, and a third disciplined, after they accessed Obama's passport files on three separate occasions between January and March of this year. An investigation into the matter is underway, and it's not clear if there was a political motivation behind the breaches.

Passport files include a person's social security number, which could then be used to access more private information from other sources.

The breaches were detected by computer checks at the State Department. Rice was informed about the issue on Thursday.

"It was not to my knowledge, and we also want to take every step to make sure that this kind of thing doesn't happen again," Rice said.

In 1992, Bill Clinton's passport records were also inappropriately accessed when he was running against President George H.W. Bush.

Richardson endorses Obama

Meanwhile, Obama has received a big boost from New Mexico Gov. Bill Richardson, a former rival for the party nomination.

Richardson, the nation's only Hispanic governor, endorsed the Illinois senator on Friday at a rally in Oregon.

In front of cheering supporters, he called Obama an extraordinary American and a "courageous, thoughtful leader." Richardson referred back to Obama's speech on the issue of race in America, which he gave earlier this week.

"He spoke to us as adults," said Richardson.

"He asked every American to see the reality and pain of other Americans ... he appealed to the best in us. As an Hispanic American I was particularly touched by his words."

Richardson then said he's been troubled by negative attitudes towards immigrants and worries that some are exploiting the issue incorrectly. He said the country's economic woes are not caused by immigrants but by what he called the disastrous policies of the Bush administration.

Richardson also reminded the crowd that "(Obama) opposed the Iraq war from the beginning," and said he has shown "courage, judgment, and wisdom."

Obama said Richardson is someone who is not driven by "raw ambition." He added he was "honoured" by the endorsement.

Both Obama and Clinton had been aggressively pursuing Richardson's endorsement as they compete for their party's nomination. The Obama campaign is hoping Richardson -- who dropped out of the race earlier this year -- will help their candidate with Hispanic voters, the fastest growing minority group in the U.S.

Richardson's Obama endorsement comes despite his close ties to the Clintons. Richardson was an ambassador and secretary of energy under President Bill Clinton. Richardson also praised Hillary Clinton, but said that Obama will bring the country together as a nation.

With files from The Associated Press