2024 election updates: Trump and Harris bring their campaigns to the battleground state of Wisconsin

President Joe Biden has cast an early ballot in the 2024 general election.

It's a bittersweet moment for Biden, who decided to end his reelection campaign in July because of growing concerns about his health and Democrats' worries about his chances of defeating former President Donald Trump. Biden voted on Monday at the state of Delaware Department of Elections, not far from his home outside Wilmington, Delaware at an early voting site, where voters were lined up down the street to cast ballots.

MORE | President Biden casts early ballot near his Delaware home after waiting in line with other voters

President Joe Biden is at a polling place in New Castle, Delaware, to vote early in the 2024 election.

According to reporters traveling with the president, there was a line of more than 100 people when he arrived. Biden walked toward the back of the line and was seen greeting and speaking with voters.

Harris criticized Trump's rally at Madison Square Garden, saying the former president is "fixated on his grievances, on himself and on dividing our country."

"It is absolutely something that is intended to and is fanning the fuel of trying to divide our country. And as I've said many times, I'll say tomorrow night in my speech, there's a big difference between he and I," Harris told reporters as she departed Joint Base Andrews for a day of campaigning in Michigan.

Asked to respond to the comments about Puerto Rico at the rally, which the Trump campaign has tried to distance itself from, Harris pointed to her support for Puerto Rico as a senator and her "opportunity economy" proposal.

"I'm very proud to have the support of folks like Bad Bunny and Jennifer Lopez and others who were supporting me before that nonsense last night at Madison Square Garden, and are supporting me because they understand that they want a president of the United States that's about uplifting the people and not berating, not calling America a garbage can, which is what Donald Trump, those are the words he has used."

Police are investigating arson at a ballot box in Portland, Oregon, where officers responded to reports of a fire overnight.

Security personnel extinguished the ballot box fire, located outside the Multnomah County elections office, and a Portland explosives unit removed the incendiary device from the box.

ABC affiliate KATU reported Monday another ballot box incident in Washington state, where police were responding to smoke coming out of a ballot box in Vancouver. The Clark County auditor told KATU that hundreds of ballots were inside the box at the time.