A man faces a murder charge after a car ploughed into a crowd of people protesting against a white supremacist rally in Virginia, killing a 32-year-old woman and injuring more than a dozen others, on a day full of violent confrontations.

Shortly after, a Virginia State Police helicopter above the rally crashed outside Charlottesville, killing the pilot and a trooper.

The chaos boiled over at what is believed to be the largest group of white nationalists to come together in a decade, protesting against plans to remove a statue of Confederate general Robert E Lee.

James FieldsThe driver of the vehicle which killed a protester has been identified as 20-year-old James Fields from Ohio (Albemarle-Charlottesville Regional Jail via AP)

That gathering sparked a counter-demonstration by others protesting against racism.

Virginia governor Terry McAuliffe declared an emergency and police in riot gear moved people away.

Matt Korbon, 22, a University of Virginia student, said several hundred counter-protesters were marching when “suddenly there was just this tyre screeching sound”.

A silver Dodge Challenger smashed into another car, then reversed, barrelling through “a sea of people”.

The impact hurled people into the air and those left standing scattered, screaming and running for safety.

The driver was later identified by police as James Fields, 20, of Ohio.

He has been charged with second-degree murder, three counts of malicious wounding, and one count related to leaving the scene. A bail hearing will take place on Monday.

Fields was photographed on the morning of the incident holding a shield with the emblem of a white supremacist group.

Vanguard America denies that Fields is a member and says it handed out shields to anyone in attendance who wanted them.

The Anti-Defamation League says Vanguard America believes the US is an exclusively white nation and uses propaganda to recruit young white men online and on college campuses.

Vanguard America confirmed via Twitter that members were in Charlottesville on Saturday morning to rally against plans to remove a Confederate statue.

In the photo by the New York Daily News, Fields stands with a handful of men, all dressed similarly in the usual Vanguard America uniform of khakis and white polo shirts.

The men hold white shields with a black-and-white logo of two axes. The Confederate statue of Robert E Lee is in the background. The paper says the photo was taken at about 10.30am and Charlottesville officials say the car crashed into the crowd, killing one, at 1.42pm.

US president Donald Trump condemned “in the strongest possible terms” what he called an “egregious display of hatred, bigotry and violence on many sides” after the clashes and called for “a swift restoration of law and order and the protection of innocent lives”.

He said he and Mr McAuliffe “agreed that the hate and the division must stop and must stop right now”.

Field’s mother, Samantha Bloom, said she knew her son was attending a rally in Virginia but did not know it was a white supremacist event.

“I thought it had something to do with Trump. Trump’s not a white supremacist,” she said.

“He had an African-American friend so …,” she said before her voice trailed off. She added that she would be surprised if her son’s views were that far right.

Ms Bloom, who became visibly upset as she learned of the injuries and deaths at the rally, said she and her son had just moved to the Toledo area from the northern Kentucky city of Florence, where Fields grew up.

The Department of Justice has opened a federal civil rights investigation into the deadly car attack.