Tens of thousands of outraged protesters from Sydney to London on Saturday kicked off a weekend of global rallies against racism and police brutality.

George Floyd, the African-American, who died in police custody last month, an unarmed black man in the US state of Minnesota, has brought thousands of protestsers onto the streets during a pandemic that is ebbing in Asia and Europe but still spreading in other parts of the world.

“It is time to burn down institutional racism,” one speaker shouted through a megaphone at a hooting crowd of thousands outside the parliament building in London.

“Silence is violence,” the throng shouted back in the rain.

Officials around the world have been trying to balance understanding at people’s pent-up anger with warnings about the dangers of a disease that has officially claimed nearly 400,000 lives globally.

Yet tens of thousands of Australians defied Prime Minister Scott Morrison’s call to “find a better way”, and thousands more in Britain ignored the health minister’s warning that the “coronavirus remains a real threat”.

“We want justice! We want to breathe!” hundreds chanted in Tunis, as demonstrations convulsing US cities spilled out across the world.

In Sydney, aborigines performed a traditional smoking ceremony at the start of a “Black Lives Matter” protest, which was sanctioned at the last minute after initially being banned on health grounds.

Many held up signs and wore face masks marked up “I can’t breathe” — the words Floyd kept repeating while handcuffed as a policeman knelt on his neck.

Floyd’s death came during the spread of a disease that has disproportionately affected black people and ethnic minorities in global centres such as London and New York.

It also came in the throes of a historic economic downturn that has statistically affected the poor and marginalised the most.

This confluence, and accompanying outrage at US President Donald Trump’s partisan response, has refocused attention on the world’s racial divides like few other events since the 1960s.

In Paris, riot police held back a crowd of several thousand who gathered outside the US embassy compound for an unsanctioned protest.

The French rallies spread to smaller cities, while in Germany it included football players from Bayern Munich, who warmed up in “Red card to racism #BlackLivesMatter” shirts.

And tens of thousands were again expected in Washington, where Mayor Muriel Bowse renamed the area outside the White House “Black Lives Matter Plaza”.

The protests have even resonated in war-scarred countries such as Iraq, where the “American Revolts” and the Arabic phrase for “We want to breathe, too” hashtags are spreading on social media.

A Minneapolis policeman accused of killing unarmed Floyd by kneeling on his neck was taken into custody on Friday and charged with third-degree murder. Three other officers with him have been fired but for now face no charges.

Earlier this week, Trump deployed thousands of “heavily armed” soldiers and police to prevent further protests in Washington, where buildings and monuments have been vandalized near the White House.

The protests turned violent across the US that left many people dead and over 4,000 people arrested on Tuesday.

A video taken by a bystander shows officer officer Derek Chauvin kneeling on his neck as he is pinned to the ground. Floyd who was unarmed and handcuffed, pleaded that he could not breathe. He was soon after declared dead at a nearby hospital.

On Wednesday, former Pentagon chief James Mattis issued a stinging rebuke of his previous boss Trump and accused him of trying to “divide” America and failing to provide “mature leadership” as the country reels from days of protests.

Police and protesters clashed in numerous cities including Chicago and New York, with officers responding to projectiles with pepper spray while shop windows were smashed in Philadelphia.

Trump has repeatedly claimed that he has “done more for the black community than any President since Abraham Lincoln,” who abolished slavery in the 1860s.

Floyd’s killing was seen as the latest example of police brutality against African Americans, which gave rise six years ago to the Black Lives Matter movement.

(With inputs from agency)