At least one person is dead and numerous others were injured Saturday afternoon after a motorist plowed into a crowd who gathered to protest a white supremacist rally in downtown Charlottesville, Va.

Video of the car mowing through the group was posted to social media. 

Charlottesville Mayor Mike Signer confirmed on Twitter one person had succumbed to their injuries. A hospital official says 19 were injured after a car plowed into a group of protesters in Charlottesville. Another report by the City of Charlottesville's official Twitter page said another "fifteen other injuries" related to the rally had been reported as of mid-afternoon. 

University of Virginia Medical Center spokeswoman Angela Taylor confirmed the death to the Associated Press.

Both President Donald Trump and Vice President Mike Pence denounced the violence via social media. 

A state official said the driver of a car that plowed into a group of marchers in Charlottesville is in police custody.

Virginia Secretary of Public Safety Brian Moran said the driver, a man, has been arrested.

Moran did not immediately provide a name of the driver.

Matt Korbon, a 22-year-old University of Virginia student, said counter-protesters were marching when "suddenly there was just this tire screeching sound." A silver sedan smashed into another car, then backed up, plowing through "a sea of people."

People scattered, running for safety in different directions, he said.

It happened about two hours after violent clashes broke out between white nationalists, who descended on the town to rally against the city's plans to remove a statue of Confederate Gen. Robert E. Lee, and others who arrived to protest the racism. 

Some onlookers caught the moment the car crashed into the crowd and posted it to Twitter, with several others tweeting about the incident:

Separately, officials say the deaths of two people in a helicopter crash near Charlottesville have been linked to the violent white nationalist rally earlier in the day.

It was not immediately clear how the crash was connected to the rally. Corinne Geller, a Virginia State Police spokeswoman, says the pilot and a passenger were killed in the crash Saturday afternoon.

The crash happened just a few hours after the vehicular incident at the rally.

Gov. Terry McAuliffe declared a state of emergency, and police dressed in riot gear ordered people at the rally in Charlottesville to disperse after chaotic clashes between white nationalists and counter-protesters.

Small bands of protesters who showed up to express their opposition to the rally were seen marching around the city peacefully by mid-afternoon, chanting and waving flags. Helicopters circled overhead. As of 12:30 p.m., a city spokeswoman said a single arrest was reported. Emergency medical personnel have responded to eight injuries related to the event.

Right-wing blogger Jason Kessler had called for what he termed a "pro-white" rally to protest the city of Charlottesville's decision to remove the Lee statue from a downtown park.

Colleen Cook, 26, stood on a curb shouting at the rally attendees to go home. Cook, a teacher who attended the University of Virginia, said she sent her son, who is black, out of town for the weekend.

"This isn't how he should have to grow up," she said.

Cliff Erickson leaned against a fence and took in the scene. He said he thinks removing the statue amounts to erasing history and said the "counterprotesters are crazier than the alt-right."

"Both sides are hoping for a confrontation," he said.

It's the latest confrontation in Charlottesville since the city about 100 miles outside of Washington, D.C., voted earlier this year to remove the statue.

In May, a torch-wielding group that included prominent white nationalist Richard Spencer gathered around the statue for a nighttime protest, and in July, about 50 members of a North Carolina-based KKK group traveled there for a rally, where they were met by hundreds of counter-protesters.

Kessler said this week that the rally is partly about the removal of Confederate symbols but also about free speech and "advocating for white people."

"This is about an anti-white climate within the Western world and the need for white people to have advocacy like other groups do," he said in an interview.

Between rally attendees and counter-protesters, authorities were expecting as many as 6,000 people, Charlottesville police said this week.

Among those expected to attend are Confederate heritage groups, KKK members, militia groups and "alt-right" activists, who generally espouse a mix of racism, white nationalism and populism.

Both the Anti-Defamation League and the Southern Poverty Law Center, which track extremist groups, said the event has the potential to be the largest of its kind in at least a decade.

Officials have been preparing for the rally for months. Virginia State Police will be assisting local authorities, and a spokesman said the Virginia National Guard "will closely monitor the situation and will be able to rapidly respond and provide additional assistance if needed."

Police instituted road closures around downtown, and many businesses in the popular open-air shopping mall opted to close for the day.

Both local hospitals said they had taken precautions to prepare for an influx of patients and had extra staff on call.

There were also fights Friday night, when hundreds of white nationalists marched through the University of Virginia campus carrying torches.

A university spokesman said one person was arrested and several people were injured.

Charlottesville Mayor Michael Signer said he was disgusted that the white nationalists had come to his town and blamed President Trump for inflaming racial prejudices with his campaign last year.

"I'm not going to make any bones about it. I place the blame for a lot of what you're seeing in American today right at the doorstep of the White House and the people around the president," said Signer.

Charlottesville, nestled in the foothills of the Blue Ridge Mountains, is a liberal-leaning city that's home to the flagship University of Virginia and Monticello, the home of Thomas Jefferson.

The Lee statue's removal is part of a broader city effort to change the way Charlottesville's history of race is told in public spaces. The city has also renamed Lee Park, where the statue stands, and Jackson Park, named for Confederate Gen. Thomas "Stonewall" Jackson. They're now called Emancipation Park and Justice Park, respectively.

For now, the Lee statue remains. A group called the Monument Fund filed a lawsuit arguing that removing the statue would violate a state law governing war memorials. A judge has agreed to a temporary injunction that blocks the city from removing the statue for six months.

Aug 12, 3:49 p.m. Updated to include information regarding the helicopter crash.