US Attorney General Jeff Sessions denounced a deadly car ramming incident in Virginia on Saturday when white nationalist activists and counter-protesters clashed, after President Donald Trump came under sharp criticism for his own tepid response.

Sessions, the top law enforcement official in the country, said “the violence and deaths in Charlottesville strike at the heart of American law and justice.”

“When such actions arise from racial bigotry and hatred, they betray our core values and cannot be tolerated,” Sessions added.

The FBI and federal prosecutors have opened a civil rights investigation into the circumstances surrounding the incident that killed one woman and wounded 19 in Charlottesville, Virginia.

Virginia Governor Terry McAuliffe had already declared a state of emergency to provide more resources to law enforcement when a sedan surged into a crowd of what witnesses said were counter-demonstrators in the picturesque university town.

US Attorney General Jeff Sessions speaks at the Department of Justice during an announcement about leaking of classified information on August 4, 2017. (AFP Photo/Brendan Smialowski)

US Attorney General Jeff Sessions speaks at the Department of Justice during an announcement about leaking of classified information on August 4, 2017. (AFP Photo/Brendan Smialowski)

Some of the injuries from the car ramming were life-threatening. A 20-year-old from Ohio, James Alex Fields, Jr, has been charged with second degree murder, malicious wounding and hit-and-run.

Two responding police officers were killed in a helicopter crash. There was no immediate indication of foul play.

Another 16 people were treated for other injuries linked to the rally, including from “individual engagements,” Charlottesville police chief Al Thomas said. Three people were arrested and charged.

Trump, speaking from his golf course in Bedminster, New Jersey, said “we condemn in the strongest possible terms this egregious display of hatred, bigotry and violence on many sides, on many sides.”

Critics focused on the president apparently equating the violence of white supremacist protesters with that of anti-fascist activists.

The president stopped short of condemning white nationalist and supremacist groups, which broadly supported Trump in last year’s election.

David Duke, a former “grand wizard” of the Ku Klux Klan who had been a key figure at the rally, urged Trump to “remember it was White Americans who put you in the presidency, not radical leftists.”

The president was quickly criticized by liberals such as his 2016 election opponent Hillary Clinton, who did not name Trump but tweeted that “Every minute we allow this to persist through tacit encouragement or inaction is a disgrace, & corrosive to our values.”

But some prominent Republicans were more direct.

Senator Ted Cruz, who lost a campaign to become the Republican presidential nominee, called on the Justice Department to investigate and prosecute the incident as an “act of domestic terrorism.”

Battle lines form between white nationalists and antifa protesters at the entrance to Emancipation Park during the "Unite the Right" rally August 12, 2017 in Charlottesville, Virginia. (Chip Somodevilla/Getty Images/AFP)

Battle lines form between white nationalists and antifa protesters at the entrance to Emancipation Park during the “Unite the Right” rally August 12, 2017 in Charlottesville, Virginia. (Chip Somodevilla/Getty Images/AFP)

“Very important for the nation to hear @potus describe events in #Charlottesville for what they are, a terror attack by #whitesupremacists,” Florida Senator Marco Rubio tweeted.

Senator Orrin Hatch of Utah, the longest-serving Republican senator in US history, said: “We should call evil by its name. My brother didn’t give his life fighting Hitler for Nazi ideas to go unchallenged here at home.”

McAuliffe, a potential Democratic presidential candidate in the 2020 elections, said: “I have a message to all the white supremacists and the Nazis who came in to Charlottesville today. Our message is plain and simple. Go home.”

Downtown Charlottesville was almost deserted by late afternoon — aside from a heavy security presence — but the city council authorized the police chief to impose a curfew, if necessary.