PHOENIX - Hundreds rallied in downtown Phoenix to demonstrate against the death of George Floyd in Minneapolis police custody a protest that turned into a clash with police.

But the cordon around the police station was eventually breached by protesters, who set fire to it and two other nearby buildings, as officers withdrew.

The family of George Floyd has been calling for the arrests of the officers involved in Floyd's death, though the issue of police brutality extends beyond one city or state - which explains the size and scale of protests happening today across America and which follow a string of similar tragic events in recent years.

Protesters blocked traffic and threw rocks at the windows of businesses and passing vehicles, according to investigators.

The demonstration began as a peaceful protest, but news outlets reported protesters began throwing objects like water bottles at officers, who responded by using tear gas on the crowd.

"Floyd, while in custody of Minneapolis police officers, were harrowing to watch and deeply disturbing", Barr said in a statement Friday.

The police station had become the centre of unrest, as it was believed that the officer accused of killing Floyd previously worked here.

Across the street from the police station, windows in almost every business had been broken.

Minneapolis Mayor Jacob Frey asked the governor of the state of Minnesota to activate the National Guard to maintain security. "These activities threaten the safety of lawful demonstrators and other Minnesotans, and both first responders and demonstrators have already been injured". An auto parts store, close to the capitol building, was seen in flames hours later.

Minnesota's USA attorney Erica McDonald pledged a "robust and meticulous investigation into the circumstances surrounding" Floyd's arrest and death. "It can't be 'normal.' If we want our children to grow up in a nation that lives up to its highest ideals, we can and must be better", the former president said. "A total lack of leadership", Trump tweeted.

"I think the tension that black parents and black teachers and black loved ones have to communicate the realities of the world as they exist to young black people and to black children so that they understand the world that they're navigating", added Smith.

In a live interview on CNN, Ellison attributed the lack of charges several days since Floyd died to prosecutors with the Hennepin County Attorney's Office "trying to be careful" to make sure they have a case that is "air tight" and won't fall apart because of pressure to file more quickly than the evidence allows. I have said many times that racism exists across the country, state and right here in Columbus.

Representatives from the US Department of Justice, as well as the FBI on Friday promised protesters a swift and thorough investigation.

"We are a country with an open wound".

In New York City, protesters disobeyed the city's ban on public gatherings during the coronavirus health crisis. "Please, please, let me stand", he's heard saying.