An autopsy commissioned by the family of George Floyd found that Floyd's death last week was caused by asphyxiation when a Minneapolis police officer kneeled on his neck for several minutes.
Floyd, a 46-year-old African American man, died last week while in handcuffs after being pinned down by a white officer, Derek Chauvin. His death, captured on video, has sparked chaotic demonstrations in dozens of American cities, some of which have turned violent. Chauvin has been charged with third-degree murder and manslaughter in the case.
The family's autopsy report found Floyd's neck and back were compressed, leading to asphyxiation.
The family-appointed medical examiner, Michael Baden, said no underlying medical conditions caused or contributed to Floyd's death.
The report comes after preliminary findings from the Hennepin County Medical Examiner found "no physical findings" to "support a diagnosis of traumatic asphyxia or strangulation." The county report found that Floyd's death was the combined result of being restrained by police as well as underlying health conditions and any potential intoxicants in his system.
Earlier Monday, U.S. President Donald Trump lambasted the nation's governors as "weak," demanding they crack down on protesters and arrest them after six nights of sometimes violent demonstrations in dozens of American cities in the wake of Floyd's death.
The U.S. leader told the governors in a video conference that they "have to get much tougher" with demonstrators after watching as Sunday night protests that often started peacefully devolved into clashes with police and other authorities clad in riot gear.
Police in several cities fired tear gas and rubber bullets at protesters to disperse them, while some demonstrators torched police cars and also ransacked and looted stores.
"Most of you are weak," Trump told the governors. "You've got to arrest people, you have to track people, you have to put them in jail for 10 years and you'll never see this stuff again."
One of the protests unfolded just across the street from the White House in Washington where Trump has his residence.
But protester clashes with police unfolded from coast to coast, perhaps the country's most widespread uprising since the extended unrest spawned by opposition to the Vietnam war in the 1960s.
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 Floyd was pinned down, he said "Let's switch it up ya'll. Let's switch it up. Do this peacefully, please."
On Monday, New York Mayor Bill de Blasio and Governor Andrew Cuomo announced a curfew beginning at 11 p.m., joining nearly 40 cities, including Los Angeles, Chicago, Miami, Detroit and Philadelphia that have imposed nighttime curfews. The governors of Texas and Virginia have imposed states of emergency.
Similar events have played out in many cities where peaceful protests by thousands of people later turned into unrest, as police holding shields and batons sought to push back lines of demonstrators, launching tear gas into crowds, while some people set fires and smashed storefronts.
There were also reports in many cities of police injuring journalists who were covering the protests.
Officers in Washington used tear gas and stun grenades to clear a crowd of more than 1,000 people from Lafayette Park, across the street from the White House. The crowd had marched from Howard University and focused their anger on police, shouting, "No justice, no peace, no racist police."
Washington Mayor Muriel Bowser ordered an overnight curfew Sunday night into Monday morning, while authorities activated National Guard troops in the capital city as well as in at least 23 states to assist police.
National Guard troops also worked with police in Atlanta to enforce an overnight curfew in the Southern city. Atlanta Mayor Keisha Lance Bottoms earlier Sunday fired two police officers and put three others on desk duty until accusations of excessive use of force Saturday night could be reviewed.
Demonstrations in the northwestern U.S. city of Portland, Oregon, remained largely peaceful into the night at which time police reported projectiles were thrown at officers and authorities used tear gas to disperse crowds.
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 was scheduled to appear in court Monday afternoon in Minneapolis.
"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," said the players from the Washington Wizards of the National Basketball Association. "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. Preventing reconciliation and driving us apart is the goal of these radical groups, and we cannot let them succeed."
Trump has blamed most of the violence during protests on "Antifa and other radical left-wing groups," and offered federal military assistance to Minnesota.
Media reports say that out of an abundance of caution Trump was taken for a brief period on Friday night by the Secret Service to a White House underground bunker.
"The White House does not comment on security protocols and decisions," a White House spokesman, Judd Deere, told VOA when asked about the reports.
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.