A woman was killed on Saturday and 34 injured, five critically, after protests turned violent in Charlottesville, Virginia, as white nationalists protesting plans to remove the statue of a Confederate general clashed with counter-demonstrators and a car plowed into a crowd, officials said.

A 32-year-old female, Heather Heyer, was among those killed, said Charlottesville Police Chief Al Thomas, and injuries ranged from life-threatening to minor. The alleged driver of the vehicle, James Alex Fields Jr., has been taken into custody and held on second-degree murder charges. Police said they were treating the incident as a criminal homicide investigation. A video shown on CNN appeared to show a silver sedan driving at high speed into the crowd before reversing.

Federal authorities have opened a civil rights investigation into the death of the 32-year-old woman.

The clashes on Saturday morning prompted the governor to declare an emergency and halt a rally over removing a Confederate general's statue from a public park.

"I am heartbroken that a life has been lost here," Charlottesville Mayor Mike Singer said on his Twitter feed. "I urge all people of good will - go home." He did not give details of who died and what caused the death.

"I am praying that God help us all," Vice Mayor Wes Bellamy said in an interview with CNN. "We are better than this."

“We’re closely following the terrible events unfolding in Charlottesville, Virginia," President Donald Trump said at a news conference. "We condemn in the strongest possible terms this egregious display of hatred, bigotry and violence on many sides."

Earlier, the governor had declared an emergency and halted a rally to protest the planned removal of a Confederate general's statue from a public park.

The fighting broke out in the city's downtown before noon when hundreds of people, some wearing white nationalist symbols and carrying Confederate battle flags, were confronted by a nearly equal number of counter-protesters. The clashes began the previous evening, resulting in four arrests.

Combatants on both sides wore helmets and held shields, and some brandished wooden poles. Militia members in the city openly carried rifles, although no gunfire was reported.

Mayor Bill de Blasio was among the NYC officials who reacted to the incident, saying in a statement, "we will not be intimidated by domestic terrorism. We will continue to fight against the deep-seated racism that exists in our country wherever it appears."   

Attorney General Eric T. Schneiderman said his "heart was with" those standing up to racism and bigotry within the country. 

"Each of us—especially those of us in public office—has a moral obligation to condemn these actions in the strongest of terms," he said in a statement. "Our diversity is our greatest strength—and we will not allow anyone to turn that strength against us.”

And New York City Council Speaker Melissa Mark-Viverito on Sunday called the rally a "disgusting, vile, and is a slap in the face of this nation's history of fighting for civil rights."

The confrontation was a stark reminder of the growing political polarization that has intensified since Trump's election. The blunt-speaking Republican, who vowed to shake up Washington's political culture, has emboldened both sides of the divide, giving rise to heated rhetoric and a wave of protests.

The clash also highlights a resurfacing of the white supremacist movement under the "alt-right" banner after years in the shadow of mainstream American politics.

"You will not erase us," chanted a crowd of white nationalists, while counter-protesters carried placards that read: "Nazi go home" and "Smash white supremacy."

Soon after the melee erupted, Virginia Governor Terry McAuliffe declared a state of emergency in the city, home of the University of Virginia's flagship campus. The gathering was declared an "unlawful assembly," allowing police to disperse the protesters, and police cleared the park where the rally was to be held.

After the crowd dispersed, dozens of law enforcement officers clad in riot gear were seen patrolling the streets, with small clusters of protesters gathered in pockets in the surrounding streets.

The clash unfolded ahead of the planned start of a "Unite the Right" rally that was expected to draw thousands of people who are angry at the planned removal of a statue of Confederate General Robert E. Lee from a public park.

Jason Kessler, a blogger who organized the rally, said in a phone interview that his group dispersed after police declared the assembly to be unlawful.

He blamed Charlottesville officials for canceling the rally. Scheduled speakers, including white nationalist Richard Spencer, were not given police protection in the melee, he added.

"Our constitutional First Amendment rights were violated," Kessler said, declining to comment on whether his group would try to stage another rally in Charlottesville.

The rally was part of a persistent debate in the U.S. South over the display of the Confederate battle flag and other symbols of the rebel side in the Civil War, which was fought over the issue of slavery.

Supporters of removing statues such as the one of Robert E. Lee call them racially insensitive, while opponents say such moves reflect "empty political correctness" and that the Confederate symbols honor Southern heritage.

David Duke, a former leader of the white supremacist Ku Klux Klan, was in Charlottesville for the rally, according to his Twitter account.

On Friday night, hundreds of white demonstrators holding flaming torches marched at the University of Virginia in a display that critics said was reminiscent of a Ku Klux Klan rally. Kessler, in an interview, denied the use of torches was tied to the notorious white supremacist group.

Eventually, both sides threw punches and pushed each other as police moved in to break up the confrontation. At least one person was arrested on Friday, and several people were treated for minor injuries, the Daily Progress newspaper said.

"The views fueling the spectacle in Charlottesville are repugnant," House Speaker Paul Ryan, a Republican, said in a message on Twitter on Saturday. "Let it only serve to unite Americans against this kind of vile bigotry."

The National Guard is on standby, with Virginia State Police coordinating security in the city of 45,000, the governor said in a statement on Friday.