Fears of violent clashes in the wake of the protests sweeping the US heightened over the weekend after a show of force by an armed black militia group.
An estimated 2,500 members of the Not F*****g Around Coalition (NFAC) took to the streets of Louisville, Kentucky on Saturday, joining a protest march over police shooting dead Breonna Taylor, a 26-year-old black nurse, in March.
Wearing black combat fatigues and carrying automatic weapons, the group outnumbered a small clutch of Three Percenters, a far-right militia group that also made an appearance at the demonstration.
The two sides were kept apart by police, and the only incident came when three members of the coalition sustained minor wounds when a gun discharged accidentally.
However, the appearance of the two armed militias raised the spectre that future confrontations may not pass off as peacefully, given the backdrop of violent protests that have swept the US following the killing of George Floyd by police in Minneapolis in May.
Entirely separate from the Black Lives Matter movement, the NFAC is willing to use violence as the group's leader "Grandmaster Jay" – whose real name is John Fitzgerald Johnson – made clear.
"We are all ex-military, we are very disciplined, we are all expert shooters," he said in one recent interview. "We don't want to negotiate, we don't want to sing songs, we don't bring signs to a gunfight. We are an eye for an eye organisation."
Carrying echoes of the Black Panther Movement of the 1960s, the NFAC is militant and separatist, according to Mr Johnson.
"The solution is very simple," he said. "We follow a declaration of liberation, declaring every African descendant of the slave trade a political prisoner here in the United States.
"Then after that, the United States has a choice, they carve us a piece of land out here – we'll take Texas and let us do our own thing – or exodus out of here and go somewhere where they will give us our own land to build our own nation."
The group first came to public attention at the beginning of the month, when around 200 activists marched on Stone Mountain Park in Georgia, a site with carvings of Confederate soldiers.
The location, associated with the resurgence of the Ku Klux Klan in the 1920s, was chosen by the NFAC in the hope of provoking a clash with the far-right. However, with Three Percenters nowhere to be seen, the NFAC claimed victory.
"I don't see no white militia, the boogie boys, the three percenters and all the rest of these scared-ass rednecks," one activist shouted through a megaphone.
Clashes between extremists have seen outbursts of violence, notably at Charlottesville, Virginia in August 2017, when a Unite the Right rally ended with the death of a counter-protester.
The emergence of NFAC represents an escalation of tension, raising fears of a serious confrontation between left and right.
"I think the threat of things getting violent is very real. These are two groups of people carrying weapons," said Julia DeCook, assistant professor at the school of communication at Loyola University Chicago, who has studied the far right.
"There has been a rise in paramilitary groups on the right. These are people who have wanted to start a war. People are realising how serious the threat of paramilitary groups is.
"The fact there is a group of armed black citizens is terrifying to groups like the Three Percenters. It is a tinderbox, and we really have to be ready for it."
Elsewhere in the US, one person was shot killed during a Black Lives Matter protest in Austin, Texas on Saturday night. It is understood the victim, a protester who was carrying a rifle, was shot dead by the driver as he approached a car.
Violent clashes between police and protesters were reported in several other cities over the weekend.
In Seattle, police used pepper spray and stun grenades in an attempt to restore order as demonstrators broke windows and started a number of fires, including at a youth detention centre.
At least 45 people were arrested and several protesters and police officers were injured as the city's police chief, Carmen Best, declared a riot.
Further south, in Portland, Black Lives Matter protests entered their 59th day. Clashes outside the Federal Court House saw nurses in hospital scrubs join military veterans, fathers and mothers in demonstrating against the presence of federal agents in the city.
In Oakland, California, demonstrators set fire to a courthouse and hurled fireworks at police. Violence was also reported in the Denver suburb of Aurora, where a protester was shot.
Chicago, one of the cities in which Donald Trump has deployed federal troops, saw a series of demonstrations with one protest calling for the police to be defunded, while another another "back the blue" rally supported the forces of law and order.