Members of white nationalists are met by a group of counter-protesters in Charlottesville, Virginia. Photograph: (Reuters)
A vehicle plowed into a crowd of people Saturday at a Virginia rally where violence had erupted between white nationalist demonstrators and counter-protesters, witnesses said.
A 32-year-old woman was killed and 19 were hurt in the ramming, police said, with injuries ranging from minor to life-threatening.
"I am heartbroken that a life has been lost here," wrote mayor Mike Signer on Twitter. "I urge all people of good will -- go home."
Ambulances quickly arrived at the scene of the car ramming, which a witness told AFP was "intentional" -- saying one girl got "tore up" after the car "backed up and they hit again."
He said the dark sedan "raced down here, jumped over the speed bumps and it backed up and it hit everyone again."
The male driver was taken into custody and police were treating the incident as a "criminal homicide," the police chief said.
An AFP journalist saw injured people on the ground and others in tears.
According to multiple witnesses, the victims were counter-protesters who had descended on Charlottesville to denounce so-called "alt-right" demonstrators, among them Ku Klux Klan and neo-Nazi sympathizers.
Virginia Governor Terry McAuliffe had earlier declared a state of emergency.
The death toll linked to the rally rose to three -- one in the car crash and two in a helicopter crash outside Charlottesville.
The cause of the helicopter crash, which occurred in a nearby wooded area, was under investigation, Virginia State Police said.
Authorities did not say how the crash was linked to the violence in Charlottesville, though it appeared state police were onboard, as Trump tweeted his "deepest condolences to the families & fellow officers of the VA State Police who died today."
He later added: "Condolences to the family of the young woman killed today, and best regards to all of those injured, in Charlottesville, Virginia. So sad!"
Hundreds had descended on Charlottesville either to march in or rail against a "Unite the Right Rally." Unrest quickly flared even as riot police and national guard troops flooded the city's downtown.
White far-right supporters, some wearing hats with Trump's "Make America Great Again" slogan and others in riot gear with shields and batons, faced off against counter-protestors as each side hurled projectiles at each other before overwhelming the police positioned between them.
Anti-racism protesters waved flags from the Black Lives Matter movement, chanting slogans like "We say no to racist fear" and "No Nazis, no KKK, no fascist USA."
Saturday's far-right rally follows a much smaller demonstration last month that saw a few dozen Ku Klux Klan-linked marchers gather to protest Charlottesville's planned removal of a statue of General Robert E. Lee, who led Confederate forces in the US Civil War.