The brother of George Floyd has spoken about his phone call with United States President Donald Trump, following Floyd’s death last week.

Floyd, a 46-year-old black man, spent his last lucid moments facedown in a Minneapolis street last Monday, with the knee of white police officer Derek Chauvin pressing firmly down on his neck as he struggled to breathe.

Bystander footage captured Floyd pleading for air, repeating over and over, “I can’t breathe, I can’t breathe” and calling for his mother before falling unconscious.

He was pronounced dead in hospital a short time later.

His death - the latest in a long list of unarmed African Americans killed by police - sparked protests and riots not only in Minneapolis, but in cities across the entire US.

At the White House on Friday, President Trump told media he had spoken to the family of Floyd, who he called "terrific people".

"I just expressed my sorrow," Trump said, adding "that was a horrible thing to witness" and it "looked like there was no excuse" for Floyd's death.

But Floyd's brother Philonise Floyd spoke to American news channel MSNBC on Saturday about their "fast" call, during which he did not feel heard by the President.

"It was so fast. He didn't give me an opportunity to even speak," he explained.

"It was hard. I was trying to talk to him, but he just kept, like, pushing me off, like 'I don't want to hear what you're talking about'.

"And I just told him, I want justice. I said that I couldn't believe that they committed a modern-day lynching in broad daylight. I can't stand for that."

Philonise also spoke about his call with Joe Biden, the presumptive challenger in the US presidential election in November.

"I asked Vice-President Biden - I never had to beg a man before - but I asked him, could he please, please get justice for my brother," he said.

"I need it. I do not want to see him on a shirt just like the other guys. Nobody deserved that. Black folk don't deserve that. We're all dying.

"Black lives matter."

Chauvin, the officer who knelt on Floyd's neck, has been charged with third-degree murder and second-degree manslaughter. Three other officers involved in the arrest have not yet been charged.

Philonise said he wanted the charge to be upgraded to first-degree murder and the three other officers also prosecuted.

"They didn't care about what they wanted to do with my brother. He wasn't a person to them, he was scum, he was nothing," he told MSNBC.

"I can imagine how many people they did like that. I don't need them on the streets to kill anybody else.

"I'm hurt, my family's hurt, his kids are hurt - they will grow up without a father. Everybody is crying and in pain right now."

He said the force used towards his brother, who police suspected of using a counterfeit $20 bill, was excessive and unjust.

"You killed him for that? ... That was hatred. That was just hatred, nobody deserves that. I'm tired of seeing it, I'm tired of this.

"I loved my brother. We all loved him. We looked up to him. He didn't deserve that."

Feature image: Getty and YouTube.