Standing near Lafayette Park, Karen Graylove of Bethesda, Maryland, carried a special placard that she had made to honor Floyd, as well as Ahmaud Arbery, a black jogger who was shot to death in Georgia in February and Breonna Taylor, a black woman whom police shot to death in her home in Louisville, Kentucky, in March.

"I can't stand racism. I can't stand man's inhumanity to man," Graylove told China Daily. "We have to admit that we are a racist society. And enough is enough."

Graylove, a yoga trainer, said she was against racial profiling and has advocated for more rigorous training of police and getting rid of bad officers.

"This is man-made disaster. This is the administration allowing racism and bigotry to exist and it's not right. It's not fair, and it's just this George Floyd that was the straw that broke the camel's back.

"Do I believe in looting? No, but you can understand people's exhaustion and their rage," she said.

Kay C. James, president of The Heritage Foundation, said the "horrific and needless" death of George Floyd must serve as a turning point to make people in the US finally end the "ugly racism" that stains the nation's history.

James, who was part of the civil rights movement of the 1960s and helped desegregate her school, said in a statement on Sunday that racism in the US is a wound that could not be cured with Band-Aids.

"The arrest of fired Minneapolis police officer Derek Chauvin on Friday on charges of manslaughter and third-degree murder is a welcome step, but it is just a Band-Aid," she said.

The solution to racism is expected to be hotly debated in the run-up to the presidential election, which is just five months away.

The Republican president, who is seeking reelection, was hearing calls from members of his own party to tone down his rhetoric.

"I think the country is definitely looking for healing and for calm," Senate Majority Whip John Thune of South Dakota said on CNN. "I think leaders right now need to have empathy and humility and respect."

Republican Senator Tim Scott of South Carolina also said he had spoken to the president over the weekend about his inflammatory tweets, which he described as "not constructive".

Presumptive Democratic presidential nominee Joe Biden has pledged that he would address "institutional racism" in his first 100 days in office.

"Hate just hides. It doesn't go away, and when you have somebody in power who breathes oxygen into the hate under the rocks, it comes out from under the rocks," the former vice-president said on Monday.