Protestors call for justice for George Floyd, a black man who died after a policeman was filmed holding his knee to Floyd's neck for more than five minutes. — AFP/VNA Photo

MINNEAPOLIS — Authorities in Minneapolis and its sister city St. Paul got reinforcements from the National Guard on Thursday as they girded for fresh protests and violence over the shocking police killing of a handcuffed black man.

After stores were looted and burned overnight Wednesday in Minneapolis, officials in the so-called Twin Cities warned they would not tolerate violence while seeking to assure that investigations into George Floyd's death were underway.

Hundreds of people began marching in Minneapolis in the late afternoon, while in St. Paul, just to the east, police said there was ongoing looting.

"We know there's a lot of anger. We know there's a lot of hurt," said St. Paul Police Chief Todd Axtel.

"But we can't tolerate people using this as an opportunity to commit crimes," he said.

"We are not going to tolerate our buildings being burned down."

At the request of both cities, Minnesota Governor Tim Walz called up hundreds of National Guard troops and state police to help with security.

"George Floyd's death should lead to justice and systemic change, not more death and destruction," he said.

Outrage spreads

Three days after a policeman was filmed holding his knee to Floyd's neck for more than five minutes until he went limp, outrage continued to spread over the latest example of police mistreatment of African Americans.

Floyd's family demanded the officer and three others who were present, all since fired from their jobs, face murder charges.

"Justice is these guys need to be arrested, convicted of murder and given the death penalty," Floyd's brother, Philonise Floyd, told CNN.

"But people are torn and hurting because they are tired of seeing black men die, constantly, over and over again."

Two national African American leaders, Jesse Jackson and Al Sharpton, arrived in Minneapolis and urged more protests.

Jackson called Floyd's death a "lynching in broad daylight."

Sharpton said videos, including police bodycam footage, were all the evidence needed to arrest the police officers involved.

"We are going to make sure that this prosecution goes down," said Sharpton.

Case is 'top priority'

The videos appeared to show that Floyd had not fought back when he was arrested Monday on a low-level charge of using a counterfeit banknote.

After his arrest, the police handcuffed him and held him to the ground, with a bystander video showing one officer pressing his knee on the neck of Floyd, who repeatedly cried that he couldn't breathe until he went silent and limp. He was later declared dead.

Local and federal investigators said they were working the explosive case as fast as they could.

"The Department of Justice has made the investigation in this case a top priority," said Erica MacDonald, the US federal attorney for Minnesota.

"To be clear, President (Donald) Trump, as well as Attorney General William Barr, are directly and actively monitoring the investigation in this case."

The White House said Trump was "very upset" upon seeing the "egregious, appalling" video footage and demanded his staff see that the investigation was given top priority.

"He wants justice to be served," Trump's press secretary Kayleigh McEnany told reporters.

Tear gas and rubber bullets

Demonstrators clashed with law enforcement, looted stores and set fires to shops and a construction site overnight Wednesday in the busy Lake Street corridor of Minneapolis, and were met with police tear gas and rubber bullets.

One person died of a gunshot wound, and police were reportedly investigating whether he was shot by a store owner.

The case of Floyd, a 46-year-old restaurant security guard, was seen as the latest in a long series of unjustified police killings of black civilians.

It evoked memories of riots in Ferguson, Missouri in 2014 after a policeman shot dead an African American man suspected of robbery, and the case earlier the same year of New Yorker Eric Garner, who died after New York police put him in an illegal chokehold as they tried to detain him for selling cigarettes.

Sympathy protests erupted in other cities.

Several hundred people demonstrated in New York's Union Square on Thursday, leading to at least five arrests.

In Los Angeles, where there are longstanding tensions between law enforcement and black residents, protesters marched on Wednesday on downtown and briefly blocked a major freeway.

Activists were planning a rally Friday in downtown Washington near the White House.

Ilhan Omar, a black Somalia native who represents Minneapolis in Congress, called for calm but said there was "extreme frustration" in the community over the incident.

"Anger really is boiling over because justice still seems out of reach," she said. — AFP