FBI probe underway into Virginia white nationalist rally violence

US authorities on Sunday are investigating the outbreak of violence in Virginia following a white nationalist rally that killed one person and injured more than 30, presenting US President Donald Trump with a major domestic challenge.

The violence in the Southern college town of Charlottesville on Saturday was widely condemned, with many politicians and activists on both the left and right also criticizing Trump, a Republican, for waiting too long to address it and when he did so, failing to explicitly condemn the white-supremacist marchers who ignited the melee.

Virginia police have not yet provided a motive for a man plowing a car into a crowd of people objecting to the white nationalists, but US attorneys and the Federal Bureau of Investigation have opened a civil rights investigation into the crash, an FBI field office said.

Four people have been arrested, including James Fields, a 20-year-old white man from Ohio who is being held in jail on suspicion of crashing the car. The vehicle killed a 32-year-old woman and injured 19 people, five of them critically.

Federal authorities were also looking into a helicopter crash on Saturday that killed two Virginia state policemen aiding efforts to quell the clashes.

On Sunday morning, Ivanka Trump, the president’s daughter and White House adviser, appealed on Twitter for Americans to “be one country UNITED. #Charlottesville.” She also posted: “There should be no place in society for racism, white supremacy and neo-nazis.”