Officials in Charlottesville in the US state of Virginia have declared a state of emergency ahead of a large march by white nationalists, BBC report.
Thousands of people are expected to join the “Unite the Right” rally against plans to remove a statue of a pro-slavery US Civil War general.
Violent clashes between far-right groups and counter-protesters have left at least two injured, police say.
President Donald Trump has condemned the violence.
On Twitter, he said: “We ALL must be united & condemn all that hate stands for. There is no place for this kind of violence in America. Lets come together as one!”
After the clashes subsided, a car rammed into a crowd of counter-protesters. It was not immediately clear how many people had been injured.
Earlier, police fired tear gas against demonstrators and said that arrests had been made after a declaration of unlawful assembly at Emancipation Park.
The state of emergency allows local authorities to request additional resources if needed, the police department said
The far-right protesters, some waving Confederate flags, carrying shields and wearing helmets, are angry about the planned removal of a statue of Gen Robert E Lee from Charlottesville. Gen Lee commanded the Confederate forces in the US Civil War of 1861-65.
The New York Times reports that some of them were chanting “You will not replace us,” and “Jew will not replace us.”
Anti-racism organisations such as Black Lives Matter have also held marches.