Biden's campaign manager, Jen O'Malley Dillon, said her team is "confident" that the former vice president will win the White House, based on the available data from states.

"Joe Biden is on track to win this election and he will be the next president of the United States," O'Malley Dillon told a virtual press conference Wednesday morning. "So we believe we are on a clear path to victory. By the afternoon, we expect that the vice president will have leads in states that put him over 270 electoral votes."

O'Malley Dillon said the campaign anticipates Biden to ultimately win the battleground states of Pennsylvania, Michigan, Nevada and Wisconsin, which would bring his tally of Electoral College votes well past the 270 mark needed to secure the presidency.

She said Georgia remains "a toss-up," but added that there are many outstanding ballots in Atlanta, an area that favors Biden. She said North Carolina is also a tight race and the campaign believes it's currently leaning toward Trump.

"Last night, the president of the United States falsely claimed that he had won this race and then demanded that votes stop being counted," she told reporters. "Let's be extremely clear about something. If Donald Trump got his wish and we stopped counting ballots right now, Vice President Joe Biden would be the next president of the United States."

ABC News projects Trump currently has the lead in Pennsylvania, Georgia and North Carolina, while Biden has a slight lead in Michigan, Nevada and Wisconsin.

With 86% of expected vote reporting nationwide, ABC News projects Biden currently has 225 Electoral College votes while Trump has 213. ABC News has not yet projected wins for Alaska, Arizona, Georgia, Maine, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.

Pennsylvania Gov. Tom Wolf said at a news conference Wednesday morning that election officials "are still at work counting the votes” and added “we may not know the results even today." 

“But the most important thing is that we have accurate results, again, even if that takes a little longer than we’re used to," he added. “I will do everything within my power to ensure that the results are fair and that every vote is counted." 

Pennsylvania’s Secretary of State Kathy Boockvar said the state is approaching 50% of the mail-in ballots being counted, but added "there’s still millions of ballots left to be counted."

Boockvar said the state had somewhere between 2.5 and 3 million mail-in ballots cast this year, or about 10 times the number of mail-in ballots than in the previous presidential election.

Sen. Marco Rubio, R-Fla., took to Twitter Wednesday morning to apparently contradict Trump's stance on counting votes.

"The result of the presidential race will be known after every legally cast vote has been counted," Rubio tweeted.

Rubio is the first Republican senator to publicly react to Trump falsely declaring victory in the presidential election and urging the national vote count to be halted.

-ABC News' Allison Pecorin

Georgia Secretary of State Brad Raffensperger said vote counting in the Peach State will "definitely" be done by the end of the day.

"By midday, we should be pretty much through it. Probably by the end of the day, we'll definitely have it done," Raffensperger told ABC's "Good Morning America" co-anchor Robin Roberts in an interview Wednesday.

"We had a successful election," he added. "Over 4.8 million Georgians voted, which is also a record turnout for a presidential election."

Once counting is done, Raffensperger said Georgia's election officials will conduct the first statewide audit of paper ballots to help verify the results and "give voters that additional layer of confidence."

"That's very important," he said.

There are 16 electoral votes up for grabs in Georgia, a key battleground state in the race to 270. With 92% of expected vote reporting, ABC News projects Trump currently has a slight lead in Georgia with 50% while Biden has 48%.

Vermont Gov. Phil Scott, a moderate Republican, told reporters this afternoon that he voted for Joe Biden for president.

Scott, who is running for reelection against Democratic Lt. Gov. David Zuckerman, is a regular critic of the White House but had not publicly announced his intention to vote for Biden prior to Election Day, though he did say back in August that he wouldn't be voting for Trump. His moderate Northeast counterparts -- Larry Hogan of Maryland and Charlie Baker of Massachusetts -- wrote-in Ronald Reagan and left the presidential spot blank, respectively.

-ABC News’ Adam Kelsey