Minnesota officials have ruled George Floyd's death a homicide, saying he suffered from a loss of blood flow due to compression on his neck while being restrained by Minneapolis police.

Floyd, a 46-year-old African American man, died last week while in handcuffs after a white officer, Derek Chauvin, kneeled on his neck for several minutes. His death, captured on video, has sparked chaotic demonstrations in dozens of American cities, some of which have turned violent.

The report from the Hennepin County Medical Examiner on Monday said Floyd died of "cardiopulmonary arrest complicating law enforcement subdual, restraint and neck compression." It also says Floyd was suffering from heart disease, fentanyl intoxication and recent methamphetamine use, but it does not list those factors in the cause of death.

The report overturns preliminary county findings, which found that Floyd's death was the combined result of being restrained by police as well as underlying health conditions and potential intoxicants in his system.

It comes hours after an autopsy commissioned by the family of Floyd found his death was caused by asphyxiation and also ruled it a homicide. The family-appointed medical examiner, Michael Baden, said no underlying medical conditions caused or contributed to Floyd's death.

Floyd's death has led to protests across the United States, which continued Monday evening.

In Washington, police set off tear gas bombs to disperse protesters outside the White House before President Donald Trump addressed the nation from the Rose Garden.

Trump threatened to deploy the U.S. military to cities to stop violent protests, calling himself "the president of law and order" and said he will "fight to protect" the American people." Earlier Monday, Trump lambasted the nation's governors as "weak," demanding they crack down on violent protesters and arrest them.

Police in Philadelphia also fired tear gas Monday along with nonlethal bullets at hundreds of protesters who were blocking an interstate before an evening curfew was set to begin.

New York City Mayor Bill de Blasio and state Governor Andrew Cuomo announced a curfew beginning at 11 p.m., joining nearly 40 other cities, including Los Angeles, Chicago, Miami and Detroit, that have imposed nighttime curfews. The governors of Texas and Virginia have imposed states of emergency.

Protests across the United States have followed a similar pattern in dozens of cities with thousands of people turning out to peacefully protest, but later some in the crowds turn to violence. Police have used shields, batons and tear gas while some demonstrators have set fires and smashed storefronts.

Floyd's brother, Terrence, pleaded with protesters Monday not to use violence, saying it is "not going to bring my brother back at all." Speaking in Minneapolis, where George Floyd died, Terrence Floyd said, "Let's switch it up, y'all. Let's switch it up. Do this peacefully, please."

There have also been reports in many cities of police injuring journalists who were covering the protests.

The marchers say they are protesting not just harsh police treatment of black men and women, but also systemic racism in the United States.

Chauvin, the officer who held down Floyd, and three other officers who were present and did not intervene, were fired last Tuesday. Chauvin has been charged with third-degree murder and manslaughter in the case.

"We are pursuing justice, we are pursuing it relentlessly," Minnesota Attorney General Keith Ellison said.

Protesters have been joined by statements of support from a variety of entities, from corporations to professional sports teams.

"We will no longer tolerate the assassination of people of color in this country," the players from the Washington Wizards of the National Basketball Association said. "We will no longer accept the abuse of power from law enforcement. We will no longer accept ineffective government leaders who are tone-deaf, lack compassion or respect for communities of color. We will no longer shut up and dribble."

Facebook announced a $10 million pledge for unspecified "efforts committed to ending racial injustice."

Attorney General William Barr called for calm in a statement Sunday.

"The continued violence and destruction of property endangers the lives and livelihoods of others, and interferes with the rights of peaceful protesters, as well as all other citizens," he said. "It also undercuts the urgent work that needs to be done - through constructive engagement between affected communities and law enforcement leaders - to address legitimate grievances."

Trump has blamed most of the violence during protests on "Antifa (anti-Fascist) and other radical left-wing groups," and offered federal military assistance to Minnesota.

Joe Biden, the presumptive Democratic presidential nominee against Trump in the November election, spoke to black community leaders in Delaware Monday, promising if elected to "deal with institutional racism" and to set up a police oversight body in his first 100 days in office.

At least 4,400 people have been arrested across the country during the past two days of protests, according to an Associated Press tally.

Numerous Minneapolis businesses suffered extensive property damage Friday as protesters randomly looted stores in a neighborhood near the site where Floyd died.

Somali American business owner Ahmed Siyad Shafi'i told VOA that vandals attacked all his of his stores overnight.

"They broke the glass, the doors, the windows," he said via Skype, "and take whatever they can take."

Shafi'i, the owner of a restaurant and clothing store in South Minneapolis, called it "unacceptable" for anyone to destroy personal property and suggested peaceful protests.

VOA Somali Service contributed to this report.