The U.S. presidential campaign neared its end on Monday in the same angry tone it began, with Republican Donald Trump calling Democrat Hillary Clinton a "phony" and Clinton accusing him of splitting the country, as a new Reuters/Ipsos opinion poll showed Clinton with a strong chance of winning.

Clinton and Trump raced through several battleground states in a last-ditch attempt to encourage their supporters to show up and vote on Tuesday.

Clinton sought to capture more support from Latinos, African-Americans and young people, while Trump looked to win over disaffected Democrats and rev up a middle class that he said has been sidelined by the political establishment.

The Reuters/Ipsos States of the Nation project gave Clinton a 90 percent chance of defeating Trump, seeing her on track to win 303 Electoral College votes out of the 270 needed, to Trump's 235.

With surveys indicating a tight race in Michigan, which Democrats have long counted on winning, both candidates made campaign appearances there. Pennsylvania, another vote-rich state, was also seen as fertile ground by both camps in the closing hours of their campaigns.

"I want to take this moment to share a message with all of the Democratic voters in our country who are thirsting for change like everybody else," Trump told a rally in Scranton, Pennsylvania. "Hillary is the face of failure."

Clinton was bolstered on the campaign trail by President Barack Obama, who spoke at the University of Michigan in Ann Arbor, urging young people who supported him in 2008 and 2012 to do the same for Clinton.

Obama, ending his second term in office with strong approval ratings, reiterated his charge that Trump is "temperamentally unfit to be commander in chief,” and he cast the wealthy New York real estate developer as out of touch with most Americans.

"In his 70 years on Earth, the Donald has never shown any regard for working folks. I don’t think he knows working people, except for the folks who clean up in his hotels and the folks who mow the fairway on his golf course," Obama said.

With only hours left before Election Day, the Clinton campaign was boosted by Sunday's unexpected announcement by FBI Director James Comey that the agency stood by its July decision not to press any criminal charges in an investigation of Clinton's email practices while she was secretary of state.

The latest opinion polls measuring popular support for each candidate showed Clinton narrowly ahead. She had a 5 percentage point lead over Trump nationally, with 44 percent to 39 percent support, according to latest Reuters/Ipsos poll.

Races in the hotly contested states of Florida and North Carolina were shifting, however, from favouring Clinton to being too close to call.

Clinton, who is trying to become the first woman elected to the White House, had a 4 percentage point lead over Trump in separate polls by Fox News and CBS News released on Monday.

Financial markets brightened on the latest twists in what has been a volatile presidential campaign. Global stock markets surged, as did the U.S. dollar, putting them on track for their biggest gains in weeks, as investors saw Sunday's announcement by Comey as boosting Clinton's chances of winning.

Clinton's comfortable lead had eroded since late last month and investors had been unnerved by the tightening race. Clinton is considered a known quantity, while Trump is considered a political wild card.

Victory is ultimately determined not by the popular vote, but by capturing a majority of the votes in the Electoral College, which awards votes on a state-by-state basis, meaning that a handful of states where the race is close assume an outsized importance.


"LED BY STUPID PEOPLE"

Trump, a former reality TV star who had never previously run for public office, began his last day of campaigning in Sarasota, Florida. He and Clinton have been locked in a tough battle Florida, with its large Hispanic-American population.

Trump gave no ground to Clinton or to polls showing her with a narrow lead. Predicting he would win, he told supporters in Sarasota that Clinton "is such a phony," saying, "We're tired of being led by stupid people."

Trump also stopped in North Carolina, Pennsylvania and New Hampshire before closing with a late-night rally in Grand Rapids, Michigan.

Clinton planned two stops in Pennsylvania and visited Michigan before wrapping up with a midnight rally in Raleigh, North Carolina. She had an evening rally in Philadelphia with Obama, first lady Michelle Obama and rock star Bruce Springsteen.

Speaking briefly to reporters in Pittsburgh, Clinton pressed her commitment to bringing the country together.

"I think that these splits, these divides that have been not only exposed but exacerbated by the campaign on the other side are ones that we really do have to ... bring the country together,” Clinton said.


COMEY SURPRISE

The FBI's Comey sent shockwaves through the race when he told Congress on Sunday that investigators had reviewed recently discovered emails and found no reason to change their July finding that there was no criminal wrongdoing in Clinton's use of a private email server, rather than a government system, while she was the top U.S. diplomat from 2009-2013.

Trump, who drew wide criticism last month when he said the election was rigged against him and that he would not yet commit to respecting the outcome, questioned the thoroughness of the FBI review and said the issue would not go away.

Tammy Regis, 42, a disabled Army veteran who served in Iraq and now lives in Palmetto, Florida, said she would not trust the outcome if Clinton wins.

"If she wins, no I won't. I just think it's really shady," Regis said, adding that she did not know why Comey "flip-flopped" on Clinton's emails.

Since entering the race in 2015 and then seeing off 16 Republican rivals to win the party nomination, Trump has challenged political norms with bombast, personal attacks and unorthodox policies, including proposals to bar Muslims from entering the United States and build a wall on the U.S. southern border with Mexico to keep out illegal immigrants.

In October, his campaign was rocked by the circulation of a 2005 video in which he boasted about groping women.

While such controversies have given Clinton the edge among women and minorities, Trump enjoys solid support among non-college-educated whites. For both candidates, turning that support into actual votes is critical to building the electoral votes needed to win.

The make-up of Congress is also at stake on Tuesday. As candidates running for the U.S. Senate and House of Representatives wrapped up their campaigns, Republicans were seen as making some gains in their quest to hold onto majority control of both chambers.