Civil rights activist Reverend Al Sharpton has told a memorial for George Floyd that the African American man's death was symbolic of four centuries of struggle for black people in America.
Mr Floyd died in police custody after former Minneapolis police officer Derek Chauvin knelt on his neck for around eight minutes.
Video from the incident shows bystanders asking Mr Chauvin to get off Mr Floyd.
Mr Floyd repeatedly cried "I can't breathe" while calling out for his mother. He died in handcuffs with his face pressed to the street.
In front of artwork depicting Mr Floyd and the words "I can breathe, now", beside flowers and Mr Floyd's golden casket, Reverend Sharpton said he and the Floyd family were organising a march in August to call for equality in policing and criminal justice.
"When I stood at that spot, the reason it got to me is that George Floyd's story has been the story of black folks," Reverend Sharpton said.
"Because ever since 401 years ago, the reason we could never be who we wanted and dreamed of being is you kept your knee on our neck.
"What happened to Floyd happens every day in this country, in education, in health services and in every area of American life.
"It's time to stand up in George's name and say get your knee off our necks."
Reverend Sharpton took aim at President Donald Trump, who walked from the White House to the nearby St John's Church where he stood for a photo with a bible after police forcibly moved on a large protest in the area.
"George Floyd should not be among the deceased," Reverend Sharpton said.
"He did not die of common health conditions. He died of a common American criminal justice malfunction. He died because there has not been the corrective behaviour that has taught this country that if you commit a crime, it does not matter if you wear blue jeans or a blue uniform, you must pay for the crime you commit.
"We cannot use Bibles as a prop. For those that have agendas that are not about justice, this family will not let you use George as a prop."
'Big George' a powerful man who had a way with words
Mr Floyd's brother Philonise shared memories of growing up together.
"All these people came to see my brother," he said.
"And that's amazing to me that he touched so many people's hearts. Because he's been touching our hearts.
"Everybody wants justice. We want justice for George. He's going to get it."
Philonise Floyd said his brother was known fondly as "Big George".
"George, he was like a general," he said.
"Every day he would walk outside there would be a line of people wanting to greet him. He was powerful, man. He had a way with words. … Everybody loved George."
A US medical examiner's report later ruled his death was a homicide.
Charges against Mr Chauvin have now been upgraded to second-degree unintentional murder, after he was previously charged with third-degree murder and manslaughter.
The other officers who were with Mr Chauvin during the incident — Thomas Lane, J Alexander Kueng and Tou Thao — have been charged with aiding and abetting second-degree murder and second-degree manslaughter.
All four were sacked shortly after video of the incident came to light.
Mr Floyd's family believe Mr Chauvin should be facing a first-degree murder charge, their lawyer Benjamin Crump said following the announcement of the upgraded charges.
The death has prompted a wave of protests and demonstrations across the United States.