Furious Donald Trump has accused the FBI of impropriety after the bureau cleared US presidential rival Hillary Clinton of criminal wrongdoing in a new email probe, lifting a cloud hanging over the Democrat as America goes to the polls on Tuesday.
FBI director James Comey told the US Congress on Sunday that the bureau found no evidence to warrant criminal charges against Mrs Clinton in a trove of newly-discovered emails.
But Republican Mr Trump told supporters it would have been impossible for the FBI to review what has been reported to be as many as 650,000 emails in so short a time and said Mrs Clinton was being protected by "a rigged system".
"Hillary Clinton is guilty. She knows it, The FBI knows it. The people know it," he told a rally in Michigan.
"Now it's up to the American people to deliver justice at the ballot box on November 8."
For her part, Mrs Clinton said the country was facing a "moment of reckoning" on election day and Americans must choose between "division and unity".
"We have to heal this country," she told a rally in Manchester, New Hampshire.
She plans to conclude her election campaign with stops in Pittsburgh, Grand Rapids, Philadelphia and Raleigh, North Carolina, on Monday.
Mr Comey's move capped a stunning chapter in the bitter, deeply divisive contest between Mrs Clinton and Mr Trump.
The director's initial decision to make a renewed inquiry into Mrs Clinton's emails public on October 28 upended the campaign at a crucial moment, sapping a surging Mrs Clinton's momentum and giving Mr Trump fresh ammunition to challenge her trustworthiness.
Mrs Clinton's campaign, furious at Mr Comey's handling of the review, welcomed Sunday's announcement. Communications director Jennifer Palmieri said: "We're glad this matter is resolved".
The new review involved material found on a computer belonging to Anthony Weiner, the disgraced former congressman and estranged husband of Clinton aide Huma Abedin. While Mr Comey was vague in his initial description of the inquiry, he said on Sunday that the FBI reviewed communications "to or from Hillary Clinton while she was secretary of state".
Based on that review, he told politicians the FBI was not changing the conclusion it reached this summer. Then, Mr Comey said, "no reasonable prosecutor" would recommend that Mrs Clinton face criminal charges for using a private email system while at the US State Department.
In financial trading on Sunday evening, Dow Jones index futures jumped about 200 points ahead of Monday's stock market opening on news of Mr Comey's announcement. The stock market, which is allergic to uncertainty close to election day, wilted after Mr Comey's notification to Congress in late October.
The FBI began investigating the handling of classified material on Mrs Clinton's private email server shortly after she announced her bid in April 2015. The issue has dogged her campaign and contributed to the questions a majority of Americans have about her honesty and trustworthiness.
Mrs Clinton appeared to be heading for a sweeping victory before Mr Comey's first letter to Congress, in which he stressed the FBI could not yet assess "whether or not this material may be significant" or how long it might take to run down the new investigative leads.
Since then, national polls and those in battleground states indicated a tightening race for the White House and for several competitive Senate seats. Democrats need to pick up four seats if Mrs Clinton wins to take back control of the chamber.
"The October surprise that came only 11 days before election day has unfairly hurt the campaign of one candidate and changed the tenor of this election," California Democratic senator Dianne Feinstein said.
Mrs Clinton still appears to hold an edge over Mr Trump in the campaign's final stretch. The Republican has a narrow path to victory that requires him to win nearly all of the roughly dozen battleground states up for grabs.
The candidates spent Sunday sprinting across swing states as they sought to lock up support ahead of election day. As the campaign's final weekend drew to a close, more than 41 million Americans had already cast their ballots in early voting.
During remarks at a black church in Philadelphia on Sunday morning, Mrs Clinton urged voters to choose "unity over division" as she sought to close a caustic presidential campaign on an uplifting note. She warned that President Barack Obama's legacy was on the line, part of her strategy to shore up black voters who may be less enthusiastic about her than the president.
"If we come together with the common vision, common faith, we will find common ground," she declared.
Mr Trump opened a furious day of campaigning in Iowa, the battleground state where he appears strongest. He also made stops in Minnesota, Michigan and Pennsylvania, three states that have reliably voted for Democrats in presidential elections, as well as Virginia, a state on which Mrs Clinton's campaign believes it has a solid hold.
Mr Trump's campaign manager Kellyanne Conway said Mr Trump planned to keep up the breakneck campaign pace through election day. After voting in New York on Tuesday morning, he is expected to return to Pennsylvania, Michigan, Ohio, North Carolina and New Hampshire.
The businessman is also facing criticism for a new ad that asserts the "establishment has trillions of dollars at stake in this election" and features photos of billionaire George Soros, Federal Reserve chairwoman Janet Yellen and Goldman Sachs chief executive Lloyd Blankfein, all of whom are Jewish.
The National Jewish Democratic Council said the ad's use of anti-Semitic stereotypes was "shocking and dangerous" but Mr Trump's campaign said criticism of the ad was "completely false and uncalled for".