NEW YORK - US President Donald Trump unabashedly insisted on Tuesday that both left- and right-wing extremists resorted to violence during a weekend rally by white nationalists in Virginia.

He said that some present were peacefully protesting plans to remove a Confederate monument when the upheaval began.

Trump, taking questions from reporters in the lobby of Trump Tower in New York, reverted to his initial comments blaming "many sides" for Saturday's violence in Charlottesville, a day after bowing to pressure to explicitly condemn the Ku Klux Klan, neo-Nazi and white supremacist groups.

"They came at each other with clubs ... it was a horrible thing to watch," Trump said during what was supposed to be an announcement about his administration's infrastructure policy. He also said left-wing protesters "came violently attacking the other group".

Trump has faced criticism from Democrats and members of his own Republican Party over his response to the deadly violence, which erupted after white nationalists converged in Charlottesville for a "Unite the Right" rally in protest of plans to remove a statue of Confederate General Robert E. Lee.

Rally participants and counter-protesters clashed in scattered street brawls before a car plowed into the rally opponents, killing one woman and injuring 19 others. A 20-year-old Ohio man, James Fields, said to have harbored Nazi sympathies, was charged with murder.

Two police officers also were killed that day in a fiery crash of the helicopter they were flying in as part of crowd-control operations.

On Saturday, Trump denounced hatred and violence "on many sides". The comment drew sharp criticism for not explicitly condemning the white nationalists.

Critics said Trump's remarks then belied his reluctance to alienate right-wing organizations, whose followers constitute a devoted segment of his political base despite his disavowal of them.

Yielding two days later to mounting criticism over his initial response, Trump delivered a follow-up message expressly referring to the "KKK, neo-Nazis and white supremacists and other hate groups" as "repugnant to everything we hold dear as Americans".

On Tuesday, former Ku Klux Klan leader David Duke immediately applauded Trump on Twitter.

"Thank you President Trump for your honesty & courage to tell the truth about

#Charlottesville & condemn the leftist terrorists in BLM/Antifa," Duke wrote, referring to Black Lives Matter (BLM) and anti-fascists.

"By saying he is not taking sides, Donald Trump clearly is," Democratic Senate Majority Leader Chuck Schumer of New York said. "When David Duke and white supremacists cheer your remarks, you're doing it very, very wrong."

"You had people in that group ... that were there to protest the taking down of a very, very important statue and the renaming of a park from Robert E. Lee to another name," Trump said.

"Was George Washington a slave owner? Will George Washington now lose his status? Are we going to take down statues to George Washington? How about Thomas Jefferson? ... Because he was a major slave owner," Trump said.

On Tuesday, Trump explained his initial restrained response by saying: "The statement I made on Saturday, the first statement, was a fine statement, but you don't make statements that direct unless you know the facts. It takes a little while to get the facts."

While saying neo-Nazis and white nationalists "should be condemned totally", Trump said protesters in the other group "also had trouble-makers. And you see them come with the black outfits and with the helmets and with the baseball bats. You got a lot of bad people in the other group, too."

Virginia Governor Terry McAuliffe said "neo-Nazis, Klansmen and white supremacists came to Charlottesville heavily armed, spewing hatred and looking for a fight. One of them murdered a young woman in an act of domestic terrorism, and two of our finest officers were killed in a tragic accident while serving to protect this community. This was not 'both sides,'" he said.

AFL-CIO President Richard Trumka became the latest of Trump's advisory American Manufacturing Council to resign in protest. Three other members of the council, the CEOs of Merck & Co Inc, Under Armour Inc and Intel Corp, resigned on Monday.

Logan Smith, a North Carolina man who runs the Twitter handle @YesYoureRacist has revealed the names of a dozen people who took part in the Charlottesville rallies. The mass exposure led to one man losing his job and another being publicly disavowed by his family.

Reuters