US rocked by George Floyd protests: 'Mayhem' as police offers shot and run over during night of violence

'Mayhem' descended on St Louis on Monday night as four police officers were shot and several officers were run over in other parts of the US.  

'Mayhem' descended on St Louis on Monday night as four police officers were shot and several officers were run over in other parts of the US.  

A disturbing series of videos has revealed shocking violence against police officers as unrest spread to more than 70 American cities over George Floyd's death.

"Some coward fired shots at officers and now we have four in the hospital, but thank God they’re alive," St Louis Police Chief John Hayden told reporters during a press conference about 1.45am Tuesday (local time).

He said two officers were shot in the leg, one was shot in the foot, and one more was shot in the arm.

"I don't think anybody understands why this mayhem is going on across the country," he said.

"I don't know what else to say," Hayden said. "This is horrible."

Meanwhile, an officer in Las Vegas was also shot, and in other parts of the country, footage emerged of several police officers being run over .

In one incident that reportedly happened in the Bronx, in New York city, shocking video shows a car ramming a police officer in an apparent hit and run. 

In a separate incident, footage shows an officer being run over as looters make their getaway in Greenwich Village. 

In Buffalo, also in the state of New York, two officers were injured when a SUV drove through a group of police officers.

Hundreds of looters have caused "anarchy" in the city of New York and police have struggled to maintain law and order.

Disturbing images also emerged from across the nation including hundreds of men wielding baseball bats and other weapons in the streets of Philadelphia.

The images come as  US President Donald Trump walked around Washington's Lafayette Square and posed in front of a boarded up church near the White House after making a brief statement.

The President made the appearance after protesters were cleared from the area with tear gas and horses, moments before he spoke, vowing to restore "law and order".

He has vowed to use the US military to halt protests over the death of George Floyd, a 46-year-old African American who died in Minneapolis police custody after being pinned beneath a white officer’s knee for nearly nine minutes.

Derek Chauvin, the 44-year-old Minneapolis police officer who kneeled on Floyd, was arrested on third-degree murder and second-degree manslaughter charges.

Three other officers involved in the arrest have not been charged.

Floyd’s death was the latest case of police brutality against black men caught on videotape and has prompted an outcry over racism in US law enforcement.

Many Americans have attended anti-police brutality marches and rallies, which have turned violent after dark each night over the last week.