WASHINGTON -  The FBI has unexpectedly released documents concerning ex-president Bill Clinton's pardon of the husband of a wealthy Democratic donor, in a surprise move just days before the election in which his wife is seeking to become America's first female president.

The release of the heavily redacted 129-page report over the pardon of trader Marc Rich - an investigation that closed in 2005 without charges - triggered questions from Democrats already angered by the FBI's probe into hundreds of thousands of newly uncovered emails possibly linked to Hillary Clinton.

While the Rich documents were published online Monday, they received little notice until they were posted on Tuesday on a Twitter account for the Federal Bureau of Investigation's division managing Freedom of Information Act (FOIA) requests that had had no posts since a year ago, except for a small handful released simultaneously on Sunday.

"Absent a FOIA litigation deadline, this is odd," said Hillary Clinton spokesman Brian Fallon.

"Will FBI be posting docs on Trump's housing discrimination in '70s?" he added, referring to Clinton's Republican rival Donald Trump, a billionaire real estate magnate.

The FBI said the documents were posted shortly after they were processed, as with FOIA materials requested three or more times.

"Per the standard procedure for FOIA, these materials became available for release and were posted automatically and electronically to the FBI's public reading room in accordance with the law and established procedures," the statement said.

The FBI indicated that this was only a "preliminary" release that could therefore be followed by more.

Rich was indicted on federal charges of tax evasion in the United States. He was a fugitive from the Department of Justice - at a time one of the FBI's most wanted - living in exile in Switzerland at the time of his indictment. He died there in 2013.

In a controversial move, Bill Clinton pardoned him on his last day in office on January 20, 2001. The FBI opened its investigation into the pardon later that year.

Rich's ex-wife Denise Eisenberg Rich, whose name was redacted from the FBI files, "has been a major political donor to the Democratic Party, and these donations may have been intended to influence the fugitive's pardon," reads a bureau note requesting that a preliminary investigation be opened.

Meanwhile, President Barack Obama made his first public comments about the FBI decision to disclose its new review into emails that could be relevant Hillary Clinton's use of a private server while she was secretary of state, and emphasized that there is no evidence that the Democratic presidential nominee had violated the law. .

Speaking to NowThisNews, an online news service, in an interview released Wednesday, Obama said he didn't want to meddle in the process. But he said it was important to follow a practice of not allowing intimations or suggestions to pervade the public's view of the case.

"I do think that there is a norm that when there are investigations we don't operate on innuendo and we don't operate on incomplete information and we don't operate on leaks," Obama said in the interview, which was taped Tuesday. "We operate based on concrete decisions that are made. When this was investigated thoroughly last time the conclusion of the FBI, the conclusion of the Justice Department, the conclusion of repeated congressional investigations was she had made some mistakes but that there wasn't anything there that was procecutable."

Hillary Clinton and Donald Trump sprinted from swing state to swing state in a fight for the last few unclaimed votes Wednesday, six days out from an election that has set the world on edge. Clinton is ahead in most polls, but a last-minute surge by the 70-year-old Trump has delighted US foes, nauseated allies and winded global financial markets.

In less than a week Americans will chose between a populist Republican who shattered political norms and a scandal-tormented Democrat vying to be America's first female president.

The choice has left many US voters cold and made the outcome difficult to predict.

One ABC News/Washington Post tracking poll on Tuesday even gave Trump a narrow lead.

The real estate mogul has been hit by scandal after scandal, accused of sexual assault, not paying taxes and having ties to Russia's Vladimir Putin and the mob.

But renewed FBI scrutiny of Clinton's use of a private email server as secretary of state has excited Republicans and underlined public doubts about the Democrat's trustworthiness.

"Investors are jittery," said Jack Ablin, chief investment officer for the BMO Bank, "market volatility has spiked."

Trump's pledge to scrap the North America Free Trade Agreement and build a wall on the southern border has made the Mexican peso a barometer for the market's unease.

The unit has weakened against the dollar by almost four percent in the last week alone.

Meanwhile stocks from New York to Tokyo swooned, wiping billions off investments and pensions.

Iran's supreme leader Ayatollah Ali Khamenei - whose regime survives by painting America as a comic-book foe - crowed that the "catastrophic reality" of the two candidates "goes beyond what even we were saying."

In Britain, a giant effigy of Trump wielding the head of his rival Clinton was to be burned during traditional bonfire celebrations.

The long and often unedifying 2016 White House race is now being fought in a few corners of a few states.

Trump, Clinton and their most prized surrogates have virtually taken up residence in Florida, Ohio and North Carolina.

The three states offer the best chance for both candidates to cross the winning threshold of 270 out of 538 electoral college votes. But the two White House hopefuls are also placing some final long-shot bets.

Clinton will travel to Arizona, which Democrats haven't won since 1996 when her husband Bill claimed the presidency by a landslide.

An Emerson poll on Wednesday had Clinton losing the state by four percentage points. But both of its Republican US Senators have opposed Trump, offering the tantalizing prospect of a shock Clinton win.

Meanwhile Trump has been campaigning in Wisconsin and Michigan, both traditionally Democrat states that polls show Clinton leading by six points or more.

And the reality TV star will spend most of Wednesday in Florida, which is likely to make-or-break his presidential dreams.

Pollster TargetSmart forecast that Clinton could win Florida - and all but bar Trump any route to the White House - by a massive eight point margin, 48 to 40 percent.

The Florida poll, conducted with the College of William and Mary, used only a small sample of voters but targeted those who had already cast ballots under the state's early voting law.

An average of earlier Florida polls by tracker RealClearPolitics gives Trump a narrow one point lead there, and TargetSmart's survey suggests many registered Republicans have switched camps. But the tumultuous race may have a few twists left.

As they jet across the country, both candidates are also winding up to their final pitch to voters.

Clinton has spent each day of the final stretch targeting specific groups of voters - women, African-Americans, Latinos - the same coalition that carried President Barack Obama to office.

The popular outgoing president has told African-American fans that he would take it as a personal insult if they did not back Clinton.

"The African-American vote right is not as solid as it needs to be," Obama told radio's Tom Joyner Morning Show, the first of a series of interviews he was giving Wednesday before heading to North Carolina to press the case.

"I guarantee you he'll dig up Michelle's garden," Obama said, warning Trump may destroy the White House vegetable patch cultivated by his even-more popular wife. "You think I'm joking?"