2024 election updates: Millions have voted early as Trump, Harris sprint to finish

At least 245 National Guard personnel across 18 states and Washington, D.C., have been either activated by their governors or are on standby, according to Pentagon officials.

Many are helping state governments with cybersecurity efforts, while others are there to assist law enforcement and first responders in the event of protests or security incidents.

There are 126 personnel activated in Alaska, Arizona, Delaware, Iowa, Illinois, North Carolina, New Mexico, Oregon, Wisconsin and Washington, a U.S. official confirmed to ABC News.

There are 119 personnel on standby in Colorado, D.C., Florida, Hawaii, Nevada, Oregon, Pennsylvania, Tennessee, Texas and West Virginia, according to the official.

That amounts to an average of about 13 personnel currently activated or on standby per state/district.

These figures could shift at the discretion of the governors, the official said.

The move to utilize the National Guard comes after authorities said ballot boxes in Oregon and Washington were set on fire with incendiary devices last month. The governors of both states said they were putting Guard units on standby to aid local law enforcement. Nevada's governor told local reporters he wanted Guard personnel on standby in Las Vegas and Carson City.

In D.C., Guard personnel will be on standby specifically to assist with the city’s fire and medical services Tuesday through Nov. 13, Pentagon press secretary Maj. Gen. Pat Ryder said during a briefing Monday.

-ABC News' Anne Flaherty and Matt Seyler

A bipartisan coalition of 51 attorneys general has penned a letter condemning violence in response to election results.

"Regardless of the outcome of Tuesday’s election, we expect that Americans will respond peacefully and we condemn any acts of violence related to the results," the coalition wrote. "A peaceful transfer of power is the highest testament to the rule of law, a tradition that stands at the heart of our nation’s stability. As Attorneys General, we affirm our commitment to protect our communities and uphold the democratic principles we serve."

"We call upon every American to vote, participate in civil discourse and, above all, respect the integrity of the democratic process," the letter continued. "Let us come together after this election not divided by outcomes but united in our shared commitment to the rule of law and safety of all Americans. Violence has no place in the democratic process; we will exercise our authority to enforce the law against any illegal acts that threaten it."

-ABC News' Beatrice Peterson

Officials in several counties across Pennsylvania continue to investigate potentially fraudulent voter registration applications, as Trump has pushed some misleading or false claims about the incident.

Authorities in Lancaster, Berks, Monroe and York counties are investigating thousands of voter registration applications they say are potentially fraudulent, according to various officials around the state. Amid the ongoing investigations, some of the applications have been confirmed to be fraudulent while some have been determined to be legitimate, according to updates.

Still, as recently as last week Trump said Lancaster County was "caught … with 2,600 votes."

"They found, as I understand it, I mean, I don't know what's happened to the last day or so, but they in Lancaster, they found 2,600 ballots, all done in by the same hand," Trump said Sunday in Pennsylvania.

But, according to the Pennsylvania attorney general, Trump's characterization is untrue. In a statement last week, the state's top prosecutor, Michelle Henry, said that "the investigations regard voter registration forms, not ballots."

On Monday, Lancaster County officials also updated that out of the approximately 2,500 applications under investigation, more than half were confirmed to be valid. According to Lancaster County Commissioner Ray D'Agostino, 57% of the applications were verified, 17% were determined to be fraudulent, and 26% are still being investigated and are either incomplete or not verified.

D'Agostino stressed that the investigation with the DA is still ongoing. "We take this very seriously," he said.

In York County, officials last week said their investigation into a batch of 3,087 applications led to 47% having been "verified as legitimate" and were approved, 29% were incomplete and are pending, and 24% were declined and are being investigated by the DA.

Election officials have emphasized that this alleged fraud was contained and stopped -- and say the instance highlights the effectiveness of the system. Henry said the fraud attempts "have been defeated."

"These attempts have been thwarted by the safeguards in place in Pennsylvania," Henry said in her statement last week.

-ABC News' Olivia Rubin

In an interview with ABC News Live on Monday, Martin Luther King III -- the son of Martin Luther King Jr. -- said his father would "be very proud of the message that the vice president is advocating" and "very supportive" of her campaign.

Arndrea Waters King echoed her husband's sentiment, saying it would be "a celebratory day for all of us."

"[Harris] is very clear that she will be a president for all of us," she added. "And so she's continuing to take that message every place that she goes."

The Kings also pushed back on the notion that the Black community, specifically Black men, are supporting Trump over Harris.

"There has always been this excitement around the vice president as the nominee amongst the entire Black community," Arndrea said. "The excitement is there, the numbers are there. And what we are seeing is that the exact opposite is true, that we are seeing Black men actually coming and voting and organizing and literally being on the forefront."

-ABC News' Kellymarie Braun, Kyra Phillips, Joshua B. Ascher, Adisa Hargett-Robinson and Ayanna Martinez