Speaking to a largely maskless crowd at Mt Rushmore, President Donald Trump said on Saturday that protesters had waged "a merciless campaign to wipe out our history" amid demonstrations against racial injustice and police brutality.
The sharp rebuke in a holiday address on Friday (local time) to mark the nation's independence follows weeks of protests across the nation, sparked by the Memorial Day killing of George Floyd by police in Minneapolis.
Some demonstrators have also destroyed or damaged Confederate monuments and statues honouring those who have benefited from slavery.
"This movement is openly attacking the legacies of every person on Mt Rushmore," Mr Trump said, adding that some on the political left hope to "defame our heroes, erase our values, and indoctrinate our children".
Mr Trump said he would establish a national garden of American heroes, which he described as "a vast outdoor park that will feature the statues of the greatest Americans who ever lived".
Mr Trump led into the announcement by paying tribute to a litany of American icons, from political figures like Ulysses S. Grant and Frederick Douglass to entertainers like Elvis Presley and Frank Sinatra.
The executive order released on Friday by the White House said the garden would feature statues of several presidents as well as other historic notables, including Davy Crockett, Amelia Earhart, Billy Graham, Harriet Tubman and Orville and Wilbur Wright.
Mr Trump's speech, intended to rev up his conservative base, comes as Mr Trump has seen his standing slump over his handling of the coronavirus pandemic and response to protests and unrest around the country.
The speech and fireworks at Mt Rushmore came against the backdrop of a pandemic that has killed more than 125,000 Americans.
The president flew across the nation to gather a big crowd of supporters, most of them maskless and all of them flouting public health guidelines that recommend not gathering in large groups.
The discord was heightened as the Trump campaign confirmed during the president's speech that Kimberly Guilfoyle, a top fundraiser for the campaign and the girlfriend of Mr Trump's eldest son Donald Trump Jr, had tested positive for coronavirus while in South Dakota.
Both Ms Guilfoyle and Trump Jr, who serves as top surrogate for the president, are isolating themselves and have cancelled public events, according to Sergio Gor, chief of staff to the Trump campaign's finance committee.
"No movement that seeks to dismantle these treasured American legacies can possibly have a love of America at its heart." pic.twitter.com/aeZpNjdLQR— The White House (@WhiteHouse) July 4, 2020
With four months until the US presidential election, Mr Trump's hopes for a second term - once buoyed by low unemployment and a roaring stock market - seem uncertain.
Amid the headwinds, Mr Trump has sharpened his focus on his most ardent base of supporters as concern grows inside his campaign that his poll numbers in the battleground states that will decide the 2020 election are slipping.
Mr Trump in recent weeks has increasingly lashed out at "left-wing mobs", used a racist epithet to refer to coronavirus and visited the nation's southern border to spotlight progress on his 2016 campaign promise to build a US-Mexico border wall.
The event, while not a campaign rally, had the feel of one as the friendly crowd greeted Mr Trump with chants of "Four more years!" and cheered enthusiastically as he and first lady Melania Trump took to the stage.
This left-wing cultural revolution will never be allowed to destroy our way of life or take away our freedom. pic.twitter.com/BZPYERHXdy— The White House (@WhiteHouse) July 4, 2020
"Today, we will set history and history's record straight.— The White House (@WhiteHouse) July 4, 2020
Before these figures were immortalized in stone, they were American giants in full flesh and blood, gallant men whose intrepid deeds unleashed the greatest leap of human advancement the world has ever known." pic.twitter.com/u5vhKZjGcg
"Those who seek to erase our heritage want Americans to forget our pride and our great dignity, so that we can no longer understand ourselves or America's destiny," Mr Trump said.
The event drew thousands of spectators, most of them without masks, even as coronavirus cases spike across the country.
The president made his speech before a big fireworks show, the first to be held at the site in more than a decade.
Hours before Mr Trump arrived, protesters blocked a road leading to the monument.
Authorities worked to move the demonstrators, mostly Native American people protesting that South Dakota's Black Hills were taken from the Lakota people against treaty agreements. About 15 protesters were arrested after missing a police-imposed deadline to leave.
Mr Trump was expecting a South Dakota show of support, with the state Republican Party selling T-shirts that feature Mr Trump on the memorial alongside George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln. But concern about the coronavirus risk and wildfire danger from the fireworks, along with the Native American groups' protests were also present.
Republican Governor Kristi Noem, a Trump ally, said social distancing would not be required during the event and masks would be optional. Event organisers were to provide masks to anyone who wanted them and planned to screen attendees for symptoms of Covid-19.
Ms Noem, in her own remarks, echoed Mr Trump's attacks against his opponents who "are trying to wipe away the lessons of history".
"Make no mistake: This is being done deliberately to discredit America's founding principles by discrediting the individuals who formed them," she said.
We believe in equal opportunity, equal justice, and equal treatment for EVERY American! pic.twitter.com/Z8fH2vmyjR— The White House (@WhiteHouse) July 4, 2020
The small town of Keystone, which is a couple of miles from the monument, was buzzing with people hoping to catch a glimpse of the fireworks and the president. Many wore pro-Trump T-shirts and hats. Few wore masks.
"This is going to rank up in the top Fourth of Julys that I talk about," said Mike Stewhr, who brought his family from Nebraska.
Mike Harris of Rapid City, who said he was a Republican, wore a mask and waved an anti-Trump flag. He also was sporting a handgun on each hip. He said he was worried the event would spark a Covid-19 outbreak.
"I think it's a bad example being set by our president and our governor," Mr Harris said.
Leaders of several Native American tribes in the region raised concerns that the event could lead to virus outbreaks among their members, who they say are particularly vulnerable to Covid because of an underfunded healthcare system and chronic health conditions.
"The president is putting our tribal members at risk to stage a photo op at one of our most sacred sites," said Harold Frazier, chairman of the Cheyenne River Sioux Tribe.
Some Native American groups used Mr Trump's visit to protest the Mt Rushmore memorial itself, pointing out that the Black Hills were taken from the Lakota people.
"This monument will never be desecrated. These heroes will never be defaced. Their legacy will never, ever be destroyed. Their achievements will never be forgotten. And Mount Rushmore will stand forever as an eternal tribute to our forefathers and to our freedom." pic.twitter.com/mR3zhGvXwn— The White House (@WhiteHouse) July 4, 2020
More than 100 protesters, many Lakota, lined the road leading from Keystone to the monument holding signs and playing Lakota music in 95-degree heat. Some held their fists in the air as cars loaded with event attendees passed by. Others held signs that stated "Protect SoDak's First People", "You Are On Stolen Land" and "Dismantle White Supremacy".
"The president needs to open his eyes. We're people, too, and it was our land first," said Hehakaho Waste, a spiritual elder with the Oglala Sioux tribe.
Several people who once oversaw fire danger at the national memorial have said setting off fireworks over the forest was a bad idea that could lead to a large wildfire. Fireworks were called off after 2009 because a mountain pine beetle infestation increased the fire risks.
Ms Noem pushed to get the fireworks resumed soon after she was elected, and enlisted Mr Trump's help. The president brushed aside fire concerns earlier this year, saying: "What can burn? It's stone."
Mr Trump has presided over several large-crowd events - in Tulsa, Oklahoma, and at an Arizona megachurch - even as health officials warn against large gatherings and recommend face masks and social distancing.
He plans a Fourth of July celebration on the National Mall in Washington despite health concerns from DC's mayor.
Mr Trump and Melania Trump plan to host events from the White House South Lawn and from the Ellipse.