8-year-old boy identified as 6th fatality in Wisconsin Christmas parade

An 81-year-old man, Wilhelm Hospel, and a 79-year-old woman, Virginia Sorenson, were among the five killed, police said at a news conference. The other victims were 71-year-old LeAnna Owen, 52-year-old Tamara Durand and 52-year-old Jane Kulich.

The suspect, 39-year-old Darrell Brooks, is charged with five counts of first-degree intentional homicide, police said. More charges are possible, police said. He's set to make his first court appearance on Tuesday.

The suspect was involved in a domestic disturbance minutes prior to the deadly crash, police said.

Besides the five killed, 48 were hurt when the suspect "intentionally drove his maroon SUV through barricades into a crowd of people," police said.

One officer fired shots to try to stop the driver, but stopped shooting because so many parade-goers were present, police said. No one was hurt by the gunfire and the officer is on administrative leave, police said.

Police said the suspect acted alone and this was not a terrorist event.

Officials said this "Norman Rockwell-type Christmas parade" has been held for decades.

In his first comments on the deadly crash, President Joe Biden said Monday, "While we don't have all the facts and details yet, we know this morning that five families in Waukesha are facing fresh grief of a life without a loved one."

"At least 40 Americans are suffering from injuries, some of them in critical condition, and an entire community is struggling, struggling to cope with the horrific act of violence," Biden said.

"Last night, the people of Waukesha were gathered to celebrate the start of a season of hope and togetherness and Thanksgiving," he continued. "This morning, Jill and I and the entire Biden family, and I'm sure all of us, pray that that same spirit is going to embrace and lift up all the victims of this tragedy, bringing recovery from the injuries and wrapping the families of those who died in support of their community."

The administration is "monitoring the situation very closely," Biden added.

-ABC News' Sarah Kolinovsky

The person being held by police is 39-year-old Darrell Brooks, multiple law enforcement sources told ABC News. Brooks has not been charged with a crime in connection with the parade incident nor has he been named a suspect.

-ABC News' Pierre Thomas, Josh Margolin, Luke Barr, Aaron Katersky

Ten of the 18 children taken to Children’s Wisconsin hospital were admitted to the ICU, including six children in critical condition, hospital officials said.

Three of the ICU patients are in serious condition and one is in fair condition.

Another eight patients were admitted in fair conditions and two of the 18 children have since been discharged, officials said.

The hospitalized children range in age from 3 to 16 and include three sets of siblings, officials said. Injuries include serious head injuries and broken bones.

Six children were sent to the operating room Sunday night and another two children will undergo surgery on Monday, officials said.

-ABC News' Josh Hoyos