Congress on Tuesday urged the president of the United States in a joint resolution to publicly condemn white supremacists and other hate groups and address the threats posed by them.

The Senate and House of Representatives unanimously adopted the resolution, which was the first congressional response to the violence on Aug. 12 in Charlottesville, Virginia.

On that day, a neo-Nazi killed a woman and injured about 20 more when he drove a vehicle into a group of counter-protesters who were demonstrating against the white supremacists in Charlottesville.

The resolution condemned "the racist violence and domestic terrorist attack", and rejected white nationalism, white supremacy, and neo-Nazism "as hateful expressions of intolerance that are contradictory to the values that define the people of the United States."

Congress also urged Donald Trump to "speak out against hate groups that espouse racism, extremism, xenophobia, anti-Semitism, and white supremacy."

It also urged his administration to "use all available resources" to "address the growing prevalence of those hate groups in the United States."

Trump first blamed "many sides," and avoided condemning the white supremacist groups as being responsible for the Aug 12 incident.

The president took almost 48 hours to speak out against the neo-Nazis, white supremacists and the Ku Klux Klan, who were all present in Charlottesville on that day.

He initially responded to the incident by saying there were "two sides to a story" and that there were "some very fine people" on both sides.

The resolution adopted in the US Congress has been passed to Trump, who then has to decide whether to sign it or not.