Tens of thousands of people defied curfews to take to the streets of US cities on Tuesday (local time) for an eighth night of protests over the death of a black man in police custody, as National Guard troops lined the steps of the Lincoln Memorial.

Clashes between protesters and police and looting of some stores in New York City gave way to relative quiet by night’s end. In Los Angeles, numerous demonstrators who stayed out after the city’s curfew were arrested. But by late evening, conditions were quiet enough that local television stations switched from wall-to-wall coverage back to regular programming.

Large marches and rallies also took place in Philadelphia, Atlanta, Denver and Seattle.

In Portland, Oregon, crowds seemed to swell before 11pm local time. Police used stun grenades and tear gas on the crowd, calling it an “unlawful assembly”. The scattering crowd shouted “peaceful protest,” back at police.

Evening curfews were ordered in dozens of cities following a week of protests over the death of 46-year-old George Floyd in Minneapolis police custody.

Although rallies on behalf of Floyd and other victims of police brutality have been largely peaceful during the day, after dark each night crowds have turned to rioting, vandalism, arson and looting. On Monday night, five police officers were hit by gunfire in two cities.

Outside the US Capitol building on Tuesday afternoon a throng took to one knee, chanting “silence is violence” and “no justice, no peace,” as officers faced them just before the government-imposed curfew.

The crowd remained after dark, despite the curfew and vows by President Donald Trump to crack down on what he has called lawlessness by “hoodlums” and “thugs” – using the National Guard or even the US military if necessary.

Some protesters briefly pushed and rocked a chainlink fence, but were encouraged by other protesters to stop. Local news media reported that the crowds dwindled by midnight.

Protests coast to coast

In New York City, thousands of chanting protesters ignored an 8pm curfew to march from the Barclays Center in Flatbush toward the Brooklyn Bridge as police helicopters whirred overheard.

The crowd, halted at an entrance to the Manhattan Bridge roadway, chanted at riot police: “Walk with us! Walk with us.”

A protester holds a placard in front of a row of Army National Guard during a demonstration over the death of George Floyd in Hollywood

A protester holds a placard in front of a row of Army National Guard during a demonstration over the death of George Floyd in Hollywood Photo: AFP

On Hollywood Boulevard in Los Angeles, hundreds of people filled the street, marching past famous landmarks of the film centre. Others gathered outside Los Angeles Police Department headquarters downtown, in some cases hugging and shaking hands with a line of officers outside.

Los Angeles was the scene of violent riots in 1992, following the acquittal of four policemen charged in the beating of black motorist Rodney King. It led to more than 60 deaths and an estimated $US1billion ($NZ1.56bn) in damage.

A Reuters/Ipsos poll released on Tuesday found a majority of Americans sympathised with the protests.

The survey conducted on Monday and Tuesday found 64 percent of American adults were “sympathetic to people who are out protesting right now,” while 27 percent said they were not and 9 percent were unsure.

More than 55 percent of Americans said they disapproved of Trump’s handling of the protests, including 40 percent who “strongly” disapproved, while just one-third said they approved – lower than his overall job approval of 39 percent, the poll showed.

In Minneapolis, Roxie Washington, mother of Floyd’s six-year-old daughter, Gianna, told a news conference he was a good man.

“I want everybody to know that this is what those officers took from me….,” she said, sobbing. “Gianna does not have a father. He will never see her grow up, graduate.”

Floyd died after a white policeman pinned his neck under a knee for nearly nine minutes in Minneapolis on 25 May, reigniting the explosive issue of police brutality against African Americans five months before the November presidential election.

Protesters chant slogans during a rally in Miami, Florida

Protesters chant slogans during a rally in Miami, Florida Photo: AFP

The officer who knelt on Floyd, 44-year-old Derek Chauvin, has been charged with third-degree murder and second-degree manslaughter. Three other officers involved were fired but not yet charged.

‘America is not a battleground’

Trump has threatened to use the military to battle the violence and has derided local authorities, including state governors, for their response to the disturbances.

The head of the US National Guard said on Tuesday (local time) 18,000 National Guard members were assisting local law enforcement in 29 states.

The Pentagon said it had moved about 1600 US Army troops into the Washington DC region.

Trump’s rhetoric and the growing role of the US armed forces has alarmed some current and former officials.

“America is not a battleground. Our fellow citizens are not the enemy,” Martin Dempsey, a retired four-star general who served as chairman of the Joint Chiefs of Staff, wrote on Twitter.

The protests come on the heels of lockdowns to prevent spread of the novel coronavirus which hit African Americans disproportionately with high numbers of cases and job losses.

Some of those who have gathered at the site of Floyd’s killing have invoked the non-violent message of the late US civil rights leader Martin Luther King Jr., assassinated in 1968, as the only way forward.

“He would be truly appalled by the violence because he gave his life for this stuff,” said Al Clark, 62, a black man who drove to the Minneapolis memorial with one of King’s speeches blaring from his truck.

“But I can understand the frustration and anger.”

– Reuters