ORLANDO, Fla. — The presidential campaign broke into a final, urgent sprint Wednesday as Donald Trump and Hillary Clinton and their allies fanned across the country, warning supporters against complacency and pressing their case to the remaining pool of ambivalent voters.

The tightness of the race - and the multiple states poised to have a pivotal effect on the outcome - was apparent in the vast distances covered by the candidates and their surrogates, as well as the tens of millions of dollars in advertising lined up to fill the airwaves in the last days.

A bullish Trump spent the day in Florida, assuring supporters that he was on the path to victory, while his running mate, Indiana Gov. Mike Pence, raced through Arizona, New Mexico and Colorado. Trump's children also campaigned in key battlegrounds on his behalf, making stops in Colorado, North Carolina, Michigan, Ohio and Pennsylvania.

"We are going to win back the White House," Trump told supporters gathered in the sweltering sun in Orlando. But he urged them to get out and vote, warning: "We don't want to blow it."

"Give us two more days, I think we're going to be winning everywhere," Trump concluded.

Clinton, who was slated to hold events late Wednesday in Nevada and Arizona, was backed by a full cast of Democratic and liberal heavy-hitters across the country, including President Barack Obama, Vice President Joe Biden, and Sens. Elizabeth Warren, D-Mass., and Bernie Sanders, I-Vt.

After arriving in Las Vegas, Clinton's first stop was the lunchroom of the Mirage Casino, where she urged workers to get out to vote early.

"Make sure you get out and vote. ... I need your help on Tuesday!" the candidate told employees, many of whom were wearing uniforms. They lined up to greet her enthusiastically, and one woman grabbed Clinton by the arm, kissed her own hand and placed it on the candidate.

Earlier in the day, Biden told a crowd in Palm Beach Gardens: "You win here in Florida, it is all over. We can go to bed early on election night!"

A few moments later, Obama made the same case to supporters in Chapel Hill, North Carolina. "So I hate to put a little pressure on you, but the fate of the republic rests on your shoulders," he told the crowd gathered on a sports field at the University of North Carolina.

In a radio interview broadcast Wednesday morning, the president expressed concern about turnout among African Americans, pressing black voters to go to the polls for Clinton to protect the policies he has implemented.

"The African-American vote right now is not as solid as it needs to be," Obama said on "The Tom Joyner Morning Show," framing the election as not only a race between Clinton and Trump, but one in which his record is on the line.

"I need everybody to understand that everything we've done is dependent on being able to pass the baton to somebody who believes in the same things I believe in," the president said.

To shore up support among black voters, Clinton released a radio ad Wednesday titled "Disrespect" that says Trump "openly mocks the African-American community." The spot will air in Pennsylvania, Florida, Ohio and North Carolina, her campaign said.

The Clinton team dipped into its bulging war chest to increase its ad investments across the country for the final week of the campaign, purchasing airtime in Wisconsin and doubling its television spending in Arizona to $1 million.

A Democratic nominee for president has not won Arizona since Bill Clinton in 1996, but polls show a competitive contest there.

In addition, the campaign is expanding its air presence in Colorado, Virginia, Michigan and New Mexico with six-figure buys.

The new spending is fueled by Clinton's large bank account. As of Oct. 19, she had more than $62 million on hand, compared with Trump's $16 million.

This week, the campaign said it raised a record $11.3 million in 48 hours online. Clinton's online fundraising has reached its highest level since she became the Democratic nominee in July, officials said, giving them the resources to blanket the airwaves.

"We're not going to leave any money on the table," said Clinton communications director Jennifer Palmieri.

The surge in donations coincides with news of a renewed FBI inquiry into Clinton's use of a private email server when she was secretary of state, a development that Democrats have angrily branded as unfair. Fundraising appeals have asked Clinton supporters to "have her back" at a difficult time.

At the same time, the controversy has invigorated Trump and his supporters. The campaign said it had raised $100 million in small-dollar donors in October - meaning it saw a huge flood of contributions in the last 11 days of the month.

Trump has been focusing heavily this week on the FBI's latest probe, often wildly exaggerating or changing key details. In Orlando, he said that all 650,000 emails that were located on a laptop belonging to Anthony Weiner, the estranged husband of Clinton aide Huma Abedin, belonged to Clinton. Officials have not yet said whether any of the emails are connected to Clinton.

In Orlando, the GOP nominee predicted that Clinton "is likely to be under investigation for many years, probably concluding in a criminal trial."

"Hillary wants to blame everyone else for her mounting legal troubles and I don't see - if you've watched her last few speeches over the last few days, she has become totally unhinged," he said. "Unbelievable. What she's saying and what she's doing it, actually, it's unbelievable. But she has no one to blame but herself."

Earlier in the day, at a rally in Miami, Trump called his Democratic rival a "very unstable person." He did not elaborate on his claim.

Obama also briefly addressed for the first time the FBI's revived review of Clinton's emails, saying in an interview with NowThis posted Wednesday that the agency does not "operate on innuendo" and emphasizing that there is no evidence that the Democratic nominee had violated the law.

Meanwhile, the deadly shootings of two police officers in central Iowa prompted two of Clinton's top surrogates to cancel a Wednesday campaign event in the state. Former president Bill Clinton and vice-presidential nominee Tim Kaine scuttled a get-out-the-vote event in Des Moines, Clinton's campaign announced.

The officers were shot in their squad cars in Des Moines and Urbandale. Authorities took a suspect into custody on Wednesday morning.

Animosity against the news media flared at Trump's rallies on Wednesday as he accused reporters of taking part in a "rigged" system. The tension was particularly acute in Miami, where the usual buffer zone between supporters and the traveling press was missing. Screaming supporters stood just inches away from reporters.

At one point, the candidate appeared to single out NBC News reporter Katy Tur for criticism, as he has done before.

"We have massive crowds. There's something happening. They're not reporting it. Katy, you're not reporting it, Katy. There's something happening, Katy. There's something happening, Katy," Trump said.

As the rally continued, one man near the press pen shouted menacingly at Tur.

Trump also lambasted both Bill and Hillary Clinton, saying, "If Hillary Clinton were to be elected, it would create an unprecedented and protracted constitutional crisis. Haven't we just been through a lot with the Clintons? Right?"

As Trump spoke, a man in the crowd kept screaming, "He's a rapist!"

Rep. Raúl R. Labrador, Idaho, was an introductory speaker at Trump's rally - a rare GOP lawmaker who traveled from out of state to campaign with the nominee. Sen. Marco Rubio, a defeated GOP primary rival locked in a tight reelection battle, did not appear with Trump.

"I'm here because what we need to do in this election is we need to elect somebody that can believe and does believe in the American Dream," Labrador said, then telling the crowd about how he grew up in Puerto Rico and ended up being a Republican. Later he added, "I need you to do everything you can for the next seven days to make America great again."

As the crowd waited for Trump to arrive, a local GOP official spoke about the importance of voting for Republicans up and down the ticket - but the crowd was distracted by a woman wearing a jail jumpsuit and a Clinton mask who posed for photo after photo.

Republican National Committee Chairman Reince Priebus also addressed supporters, saying in Miami that while Trump is "not politically correct," he doesn't lie like Clinton.

"We're in a battle for freedom," Priebus said, "and Donald Trump will fight for our freedom."

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Phillip reported from Las Vegas and Gold reported from Washington. Anne Gearan and David Nakamura in Washington and Juliet Eilperin in Chapel Hill, N.C., contributed to this report.