Live election 2024 updates in the Philadelphia region and the focus on Pennsylvania

In what campaign aides are classifying as his "closing message" speech, former President Donald Trump is already setting expectations for his supporters to challenge the results of the election, saying Vice President Kamala Harris only has a 4% chance of winning the race.

"So based on what I'm hearing -- she's at 4%. And so we never want to take anything for granted. But we're really doing well," Trump said during his rally in Pittsburgh, Pennsylvania.

Trump again falsely accused Democrats of cheating in the 2024 election, but added that it's "too big to rig."

"I do believe it is too big to rig. They'll try. And they are trying, you know, though. It's too big to rig. This is a big movement," Trump said.

Doubting the fact that President Joe Biden legitimately won the 2020 Election, Trump said that he has since learned.

"This is that big, powerful, vicious party -- that's a vicious machine. They can take all these bad ideas and win elections." he said.

The comments come as the Trump campaign has 230,000 poll observers along with 500 attorneys in every battleground state.

-ABC News' Soo Rin Kim, Lalee Ibssa and Kelsey Walsh

Vice President Kamala Harris made two stops at residents' homes in Reading, Pennsylvania, and asked for their votes.

At the first stop, Harris greeted a family and followed them to their door so that she could talk to them.

At the second stop, Harris rang the doorbell and surprised the residents, a couple. She hugged the woman who answered the door.

"You know, it's the day before the election, and I just wanted to come by and say I hope to earn your vote and wanted to just thank you for just giving us the time for this conversation," Harris told the couple, before they conversed together briefly on one of her recurring campaign messages: finding common ground.

The woman said that Harris had received her vote already, and that she would be working the polls on Tuesday, while her husband would be voting on Election Day.

-ABC News' Gabriella Abdul-Hakim, Fritz Farrow, Will McDuffie and Oren Oppenheim

The stage is set for the Harris campaign's massive election Eve rally on the Benjamin Franklin Parkway in Center City.

Performers for the event, which is right outside the Philadelphia Art Museum, were doing soundchecks hours before taking the stage at 8 p.m. Monday.

Among the star-studded lineup are Lady Gaga, Oprah, The Roots, Jazmine Sullivan, Freeway and Just Blaze, DJ Cassidy, Fat Joe, DJ Jazzy Jeff, Ricky Martin, and Adam Blackstone.

Harris campaign's Election Eve rally on Ben Franklin Parkway draws lengthy lines as event kicks off

To end the night off, Vice President Kamala Harris is expected to take the stage later in the evening.

As of approximately 6 p.m., attendees were filling the area. Chopper 6 was above the scene and captured the long lines as people waited to get by security.

The security checkpoint was located at 22nd Street, but the line extended all the way back to Logan Square and snaked by to 22nd Street on Monday afternoon.

City officials told Action News they're prepared to handle such a large event and for Election Day, which is Tuesday.

"We have expanded our area of control, we have expanded our staffing over the next couple of days. Some people may be concerned about the event this evening. We have a full staff on location. We've expanded the hours of our men and women. We will be prepared to respond to anything that happens tomorrow and anything that flows from that this week," noted Philadelphia Police Commissioner Kevin Bethel.

Former President Donald Trump held a rally at Reading's Santander Arena on Monday to deliver his closing message to voters before Election Day.

Trump made four stops along the campaign trail, two of which were right here in Pennsylvania.

The Keystone State's 19 electoral votes are widely regarded as the votes that can swing this election either way.

"We are at the two-yard line, maybe the one-yard line," said Trump. "But it's in our hands and let me tell you, it will also be something much more important than that. It's going to save our country because our country is in trouble, but that's all you need to know. And another thing you want to know is Kamala broke it and I will fix it, and fast."

Trump rallies at Reading's Santander Arena | Walter Perez reports for Action News on Nov. 4, 2024

Trump brought his children on stage at his rally in Reading after he gave them a shoutout from the podium and appeared to get wistful in one of his final campaign events of the 2024 election, saying, "This is our last time now, for forever."

His children Eric, Don Jr. and Tiffany, along with Eric's wife and Republican National Committee co-chair Lara Trump and Tiffany's husband Michael Boulos, all appeared with the Republican presidential candidate on stage.

Trump's children, as well as Lara, each addressed the crowd, including a rare turn speaking from Tiffany.

"They're kind people," Donald Trump said. "They have big hearts. They're strong. They can be nasty. But they have big hearts, those great children of mine."

The Associated Press contributed to this report.