Black Lives Matter: Portland protester accidentally sets himself on fire

Protesters retreat through tear gas as Portland police disperse a protest against police brutality and racial injustice. Photo / Getty Images

Shocking footage has captured the moment a protester set himself on fire with a Molotov cocktail as unrest gripped major US cities.

It was filmed in Portland on the west coast where 100 days of Black Lives Matters protests have gripped the city.

Uploaded onto Twitter over the weekend, it shows burning bottles crashing against the footpath in Portland, one of which drops dangerously close to a protester.

The man in a red beanie can be seen frantically running away after he emerges from a huge blaze. The person filming can be heard calling him a "f***ing idiot".

An enormous fire can be seen burning in the middle of the street as the rioter desperately tries to put out the flames burning his body.

He can be seeing rolling on the ground in an effort to smother the flames as a group of people rush over to help.

ANTIFA lights themselves on fire—

5 minutes into the March, officers attempted to put him out. pic.twitter.com/FVBoEeQJVH

— Tayler Hansen (@TaylerUSA) September 6, 2020

"Take your shoes off," one person shouts, while another says, "Smother it, smother it!"

Riot police can be see going over to help the burning man.

About 30 seconds into the footage, police can be heard on a loudspeaker saying: "This has been declared a riot."

There are further explosions as police ask protesters to disperse.

Police used tear gas and arrested dozens of people as hundreds gathered to demonstrate against racism and police brutality.

At least one person was injured by the fire bombs, police said.

Oregon State Troopers and Portland police advance through tear gas and fire works while dispersing a protest against police brutality and racial injustice. Photo / Getty Images

"It was day 100 for Black Lives Matter protests in Portland since George Floyd's murder and they wanted to prevent us from marching," said 20-year-old protester Jay, told AFP.

"It's our constitutional right to be here and to express ourselves."

Police said people were "engaging in tumultuous and violent conduct thereby intentionally or recklessly creating a grave risk of causing public alarm".

"This is a riot. Police are giving announcements to disperse. People are throwing Molotov cocktails," Portland Police said on Twitter.

The nightly protests were sparked by the death of George Floyd while in police custody in Minneapolis in May.

Oregon State Troopers and Portland police advance through tear gas and fireworks while dispersing a protest against police brutality and racial injustice. Photo / Getty Images

Floyd's death triggered similar protests nationwide, but it is in Portland – a city of 650,000 that is more than 70 per cent white – where activists have remained on the streets practically every night, demanding racial justice and police accountability.

Over the weekend, violence escalated in other US cities including Los Angeles, Rochester, Pittsburgh and Tallahassee as Antifa activists took to the streets over the Labour Day weekend.

US President Donald Trump has cast the city as being under siege by "thugs" engaged in "domestic terrorism", though the demonstrations have been peaceful for the most part.

Tensions escalated again last weekend after a man identified as a supporter of a right-wing group was shot and killed.