Trump denounces white supremacist groups by name after Virginia violence

US President Donald Trump, under pressure to explicitly condemn a weekend rally by white supremacists that ended in bloodshed, denounced racism on Monday and slammed the Ku Klux Klan and neo-Nazis as "repugnant."

Trump had taken heat from Democrats and Republicans alike for his response to Saturday's violence in Charlottesville, Virginia.

A woman was killed and 19 others injured when a suspected Nazi sympathiser ploughed his car into a crowd of anti-racism protesters after a violent rally by white supremacists over the removal of a Confederate statue.

After meeting with Attorney General Jeff Sessions and new FBI Director Christopher Wray, Trump got tough.

"Those who spread violence in the name of bigotry strike at the very core of America," Trump said in nationally televised remarks from the White House, where he travelled early on Monday to meet with his top law enforcement aides.

"Racism is evil. And those who cause violence in its name are criminals and thugs, including the KKK, neo-Nazis, white supremacists and other hate groups that are repugnant to everything we hold dear as Americans," he said.

"To anyone who acted criminally in this weekend's racist violence, you will be held fully accountable. Justice will be delivered."

America's leaders must honor our fundamental values by clearly rejecting expressions of hatred, bigotry and group supremacy. - Merck CEO Kenneth Frazier

Critics said Trump had waited too long to address the bloodshed, and slammed him for stating initially that "many sides" were involved, rather than explicitly condemning white supremacists widely seen as sparking the melee.

A 20-year-old man, said to have harboured Nazi sympathies as a teenager, is facing charges for allegedly ploughing his car into protesters opposing the white nationalists, killing Heather Heyer and injuring 19 people. The suspect, James Alex Fields, was denied bail at an initial court hearing on Monday.

In a strong rebuke to the president, the chief executive of one of the world's largest pharmaceutical companies, Merck & Co Inc, resigned from a manufacturing panel led by Trump, citing a need for leadership countering bigotry.

CEO Kenneth Frazier, who is black, did not name Trump or criticise him directly in a statement posted on the drug company's Twitter account, but the rebuke was implicit.

"America's leaders must honor our fundamental values by clearly rejecting expressions of hatred, bigotry and group supremacy," said Frazier.

Late on Monday, Under Armour CEO also resigned from the panel, citing the apolitical nature of the company.

Trump was quick to lash out at Frazier's move.

"Now that Ken Frazier of Merck Pharma has resigned from President's Manufacturing Council, he will have more time to LOWER RIPOFF DRUG PRICES!" the president said on Twitter.

Earlier Monday, Sessions said in an interview on ABC's "Good Morning America" program that the car attack "does meet the definition of domestic terrorism."

"You can be sure we will charge and advance the investigation towards the most serious charges that can be brought because this is unequivocally an unacceptable, evil attack," he told ABC.

The Justice Department has launched a civil rights inquiry in connection with the incident.

The Charlottesville mayor, Michael Signer, a Democrat, laid much of the blame for the violence directly at the president's feet, saying on CBS that Trump had created an atmosphere of "coarseness, cynicism (and) bullying."

Of the 19 people injured on Saturday, 10 remained hospitalised in good condition and nine had been released, the University of Virginia Health System said.

Two state police officers involved in the law enforcement deployment for the rally also died on Saturday in a helicopter crash.

Trump faced criticism during last year's presidential campaign for failing to quickly reject a vow of support from a former Ku Klux Klan leader, David Duke, though he eventually did so. Duke attended Saturday's rally.

The president has long had a following among white supremacist groups attracted to his nationalist rhetoric on immigration and other hot-button issues.