TAMPA, FLA. -- U.S. President Donald Trump and Democratic rival Joe Biden are encouraging voters to turn out in person on Election Day next Tuesday, both campaigning in Florida, a state all but essential to the Republican's pathway to another term.

More than 73 million Americans have already voted, absentee or by mail, and Trump and Biden are trying to energize the millions more who will vote on Tuesday. While the Election Day vote traditionally favours Republicans and early votes tend toward Democrats, the coronavirus pandemic, which has killed more than 227,000 people in the United States, has injected new uncertainty.

Trump and Biden were appearing in Tampa hours apart on Thursday. They're visiting the western end of the state's Interstate 4 corridor, an area known for rapid residential growth, sprawling suburbs and its status as an ever-changing, hard-fought battleground during presidential elections.

"You hold the power. If Florida goes blue, it's over," Biden told supporters Thursday.

Trump was celebrating a new federal estimate that the economy grew at a stunning 33.1% annual rate in the July-September quarter -- by far the largest quarterly gain on record -- making up ground from its epic plunge in the spring, when the eruption of the coronavirus closed businesses and threw tens of millions out of work.

"So glad this great GDP number came out before November 3rd," Trump said in a tweet, predicting dire consequences if Biden is elected.

But economists warned that the economy is already weakening again and facing renewed threats as confirmed viral cases are surge, hiring has slowed and federal stimulus help has largely run out.

Biden, in a statement, criticized Trump over the report. "The recovery is slowing if not stalling," he said, "and the recovery that is happening is helping those at the top but leaving tens of millions of working families and small businesses behind."

The visits come as Biden has framed his closing argument to voters on responsible management of the COVID-19 pandemic and Trump promises that the nation is on course to "vanquish the virus" even as it sets records for confirmed new infections.

Trump is holding hold three rallies on Saturday in Pennsylvania before launching on a whirlwind tour of battlegrounds including Florida, Michigan, Georgia and Pennsylvania in the closing 48 hours of the race.

Biden, meanwhile, heads later in the week to three more states Trump won in 2016: Iowa, Wisconsin and then Michigan, where he'll hold a joint Saturday rally with former President Barack Obama. Biden's campaign also announced he will visit Minnesota Friday hours before Trump holds a rally in one of the few Clinton-voting states Trump is hoping to pick up this year.

The pandemic's consequences were escalating, with deaths climbing in 39 states and an average of 805 people dying daily nationwide -- up from 714 two weeks ago. The sharp rise sent shockwaves through financial markets, causing the Dow Jones Industrial Average to drop 900-plus points.

Trump, who frequently lauds rising markets, failed to mention the decline on Wednesday.

Trump is betting on the GOP's vast field and data operations, and efforts known as "poll flushing" -- monitoring precinct lists for who has and has not yet voted -- to provide a late boost of votes on Election Day. The Republican National Committee, which has more than 3,000 field staff and claims more than 2.5 million volunteers, will use that information to reach out to Trump supporters to ensure they get to the polls.

Nowhere may those efforts be more important than in Florida. Without the battleground state's 29 electoral votes, Trump's path to victory is exceptionally difficult.

Trump was introduced in Tampa by his wife, first lady Melania Trump, who praised her husband's presidency, saying "under Donald's leadership, we have blocked out the noise and focused on you, the American people."

Trump is banking on local news coverage of his visit to overcome a substantial advertising deficit stemming from a late cash crunch. Biden and his allies are outspending Trump and his backers by more than 3-to-1 in Florida -- about $23 million to about $7 million -- in the final push to Election Day, according to data from ad tracking firm Kantar/CMAG.

Biden, meanwhile, is pouring tens of millions of dollars into a torrent of online advertising that will deliver his closing message of the presidential campaign, highlighting his promise to govern for all Americans while blasting Trump's handling of the coronavirus pandemic.

"I'm running as a proud Democrat, but I will govern as an American president," Biden says in one of the digital ads, which will take over the masthead of YouTube.com on Thursday. "I will work as hard for those who don't support me as those who do. That's the job of a president -- the duty to care for everyone."

How much exactly Biden will spend is unclear. His campaign says it is putting a "mid-eight figure" dollar amount behind over 100 different ads, which means they could be spending as little as $25 million -- but potentially much more.

The ads will run on social media platforms including Instagram and Facebook, streaming services such as Hulu and music applications like Pandora.

The Republican National Committee, meanwhile, launched its closing message to voters Thursday, not mentioning Trump, in an apparent aim to help GOP candidates up and down the ballot with a focus on traditional Republican messages around lowering taxes and health care.

In both Hillsborough County, which includes Tampa, and the adjacent Pinellas County, Democrats are crushing vote-by-mail. As of Wednesday morning, more than 53,000 Democrats had voted by mail in Hillsborough than Republicans. In Pinellas, the largest of the four counties in the state to switch from Obama to Trump in 2016, that number was just shy of 30,000 more Democrats voting by mail than Republicans.

Republicans in both counties have a slight edge in the state's in-person early voting, which began last Saturday as Trump himself voted in Palm Beach County downstate, and the GOP will likely need a strong showing on Tuesday to overcome Democratic leads.

Because of concerns about submission deadlines, Postal Service backlogs and the potential for drawn-out legal challenges, Democrats are pressing their backers who have yet to return ballots to head to the polls in person.

The aftereffects of Hurricane Zeta were holding back voters at a number of polling places in northern Florida and northern Georgia that lost power. In Georgia, state officials weren't sure how many of the 336 early voting locations statewide were closed or delayed in opening. In Douglas County, in Atlanta's western suburbs, all six polling locations were without power, as were county offices.

Miller reported from Washington and Jaffe from Ft. Lauderdale, Florida. Associated Press writers Tamara Lush in Tampa, Florida, Michelle Price in Bullhead City, Kathleen Ronayne in Phoenix, and Will Weissert and Brian Slodysko in Washington contributed to this report.