U.S. hospital officials in Charlottesville, Virginia, say one person was killed and 19 were injured on August 12 by a car that plowed through a crowd protesting against a rally of white supremacists and far-right activists.
Video footage of the incident shows the car being driven at high-speed, striking and injuring many people, before it slammed into the back of another car and then sped away in reverse.
Virginia Secretary of Public Safety Brian Moran said the driver, a man, was arrested.
Earlier in the day, Virginia Governor Terry McAuliffe declared a state of emergency and troops from the National Guard were deployed to bolster security after clashes broke out between white supremacists and counterprotesters.
Officials in Charlottesville had approved the right-wing rally for August 12 -- a protest against the city's decision to remove a statue of General Robert E. Lee, the Confederate military leader during the American Civil War.
But permission to hold the rally was withdrawn after street clashes on the morning of August 12.
Shortly before the car plowed through the crowd, U.S. President Donald Trump sent a Twitter message urging people to unite.
Trump said: “We ALL must be united & condemn all that hate stands for. There is no place for this kind of violence in America. Let’s come together as one!”