Election 2020 updates: Biden warns of 'dark winter,' pushes masks in pandemic plan

Biden's campaign manager, Jen O'Malley Dillon, said Trump's call to shut down vote counting was "outrageous, unprecedented, and incorrect."

"It was outrageous because it is a naked effort to take away the democratic rights of American citizens," Dillon said in a statement early Wednesday morning.

"It was unprecedented because never before in our history has a president of the United States sought to strip Americans of their voice in a national election," she continued. "Having encouraged Republican efforts in multiple states to prevent the legal counting of these ballots before Election Day, now Donald Trump is saying these ballots can’t be counted after Election Day either."

"And it was incorrect because it will not happen," she added. "The counting will not stop. It will continue until every duly cast vote is counted. Because that is what our laws -- the laws that protect every Americans' constitutional right to vote -- require."

ABC News projects Republican Sen. Steve Daines will win reelection in Montana against the Democratic challenger, Gov. Steve Bullock.

Bullock, a red state Democratic governor, was reportedly recruited by national Democrats in Washington, including former President Barack Obama, to run for the Senate seat after his failed presidential bid.

It was the sixth most expensive Senate race in a cycle of ultra-expensive races, coming in at $172,578,715 spent, as Democrats pursued a path to their hopeful Senate majority through Montana.

-ABC News' Meg Cunningham

More than an hour after Biden addressed the nation, Trump took the stage at the East Room of the White House and falsely declared victory.

"We will win this and, as far as I'm concerned, we already have won it," Trump said.

ABC News projects that he has won the states of Florida, Ohio and Texas. But votes are still being counted across much of the nation, and there are millions of mail-in absentee ballots that have not yet been counted.

Trump also claimed Democrats were "trying to disenfranchise" the millions of people who voted for him, calling it "a major fraud in our nation" and saying he "won't stand for it."

"We'll be going to the U.S. Supreme Court," he said. "We want all voting to stop."

The president does not have the power to stop vote counting, and his claims of victory and fraud were baseless.

State officials have told ABC News repeatedly that they count their votes in accordance with state law and it will take time.

ABC News has not yet projected several key swing states, including Pennsylvania, Georgia, Michigan, North Carolina and Wisconsin. In each of those states, there are significant portions of outstanding votes in Democratic areas and, in many cases, those votes were early or absentee which state election officials have said would not be fully counted immediately.

Pennsylvania's three largest counties - which sent out the most absentee ballots to voters, will continue counting their mail-in ballots through the night, and into Wednesday. 

Allegheny County has scanned and uploaded 151,022 mail and absentee ballots, less than half of the 340,000 mail-in ballots received as of this early this morning.  

In addition to finishing that process over the next few days, they will also have to process any ballots they receive between now and Friday. 

While the in-person vote could be fully uploaded Wednesday, it's likely that it will take several additional days for a full count of absentee mail-in ballots. 

Updates are continually made to their count online every 15 minutes or so. 

Philadelphia is continuing to process absentee ballots received, in addition to those that will come in between Wednesday and Friday. They won't have another update to their count until tomorrow morning, after 9 a.m. The city's mail-in vote count is not currently reflected on the state's website.

Montgomery County, the state's third largest county, will continue counting through the night, and is not expected to provide any additional updates this evening. 

-ABC News’ John Santucci, Adam Kelsey, Benjamin Siegel and Alex Hosenball