A driver accused of deliberately ramming his car into anti-racism protestors at a white nationalist rally in Charlottesville, Virginia, has been arrested and charged with second-degree murder.

James Alex Fields Jr, 20, allegedly killed a 32-year-old woman and injured 25 others by ploughing into marchers carrying signs that read "Black lives matter" and "Love" on Saturday.

Eyewitnesses claim the victims were hit when a silver Dodge Challenger came speeding through "a sea of people" and smashed into another car.

Mr Fields Jr, of Maumee, Ohio, was later arrested and charged with murder, malicious wounding and failing to stop at a deadly accident, according to police.

He remains in custody. Police have not yet provided a motive for the incident but US attorneys and the FBI have opened a civil rights investigation into the crash.

In this handout provided by Albemarle-Charlottesville Regional Jail, James Alex Fields Jr. of Maumee, Ohio poses for a mugshot after he allegedly drove his car into a crowd of counter-protesters killing one and injuring 35 on August 12, 2017 in Charlottesville, Virginia. (Photo by Albemarle-Charlottesville Regional Jail via Getty Images) (Getty Images North America)

The news came as Virginia governor Terry McAuliffe called on the neo-Nazis, skinheads and members of the Ku Klux Klan who descended on the city to "go home".

He told a press conference: "I have a message for all the white supremacists, and the Nazis who came into Charlottesville today.

"Our message is plain and simple: Go home. You are not wanted in this great commonwealth. Shame on you. You pretend that you're patriots, but you are anything but a patriot.

"You came here today to hurt people. And you did hurt people. But my message is clear: We are stronger than you."

At least 41 people were treated for injuries in hospital following violent clashes between white supremacists and anti-fascists at the rally protesting against the removal of a statue to a Confederate general in the city.

A police helicopter also crashed, killing the two officers on board.

A state of emergency was announced by the local and state governments with police declaring the "Unite the Right" rally an unlawful assembly and ordering the crowds to disperse. The state police were deployed, with riot police and the National Guard waiting in the wings.

Some of the far-right group members were seen carrying assault rifles and wearing paramilitary clothing, while others had large shields, helmets and gas masks in apparent anticipation of violence ahead of the demonstration against plans to take down the statue to General Robert E Lee from a local park.

Graphic footage shows the moment Mr Fields Jr allegedly rammed his car into a group of people before reversing and hitting more people.

Medics carried the injured, bloodied and crying, away as a police tank rolled down the street.

Virginia governor declares state of emergency over white nationalist rally

Earlier the two groups of protesters were involved in violent clashes with pepper spray — used, reportedly, by both sides — filling the air, according to local media reports. Bottles were also thrown and a number of fist fights broke out.

Hospital officials said 26 were injured as a result of the car crash and 15 others from the fighting in the streets. Some were said to have life-threatening injuries.

Charlottesville Mayor Michael Signer, who confirmed one person had been killed, said he was disappointed the white nationalists had descended on his town and blamed Donald 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 America today right at the doorstep of the White House and the people around the President," he said.

Mr Trump put out a tweet condemning "violence" and "hate" - although he did not specify that he was talking about the white supremacists, attracting criticism on Twitter. He later blamed hatred "on many sides" for the violence, prompting a furious backlash from some leading Republicans.

The clash was the latest in a series of confrontations after Charlottesville, situated about 100 miles from Washington DC, voted to remove the statue of General Lee.

Celebrating the Confederate cause is a highly inflammatory issue in the US because the southern states supported slavery.

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

Charlottesville is normally a quiet university city, and many of those protesting are believed to be from out of town.