Washington: US President Donald Trump has blamed Antifa activists for violence at protests over police killings of black people, but Antifa isn't an organization and targeting it isn't so simple.
A look at what Antifa is and is not:
WHAT IS ANTIFA?
Short for "anti-fascists," Antifa is not a single organisation but rather an umbrella term for far-left-leaning militant groups that confront or resist neo-Nazis and white supremacists at demonstrations.
There is no hierarchical structure to Antifa or universal set of tactics that makes its presence immediately recognisable, though members tend to espouse revolutionary and anti-authoritarian views, said Mark Bray, a historian at Rutgers University and author of "Antifa: The Anti-Fascist Handbook."
"They do different things at different times in different ways, some of which there is evidence of them breaking the law. Other times there is not," Bray said.
Literature from the Antifa movement encourages followers to pursue lawful protest activity as well as more confrontational acts, according to a 2018 Congressional Research Service report.
The literature suggests that followers monitor the activities of white supremacist groups, publicize online the personal information of perceived enemies, develop self-defense training regimens and compel outside organizations to cancel any speakers or events with "a fascist bent," the report said.
People associated with Antifa have been present for significant demonstrations and counter-demonstrations over the last three years, sometimes involving brawls and property damage.
They mobilized against a white supremacist march in Charlottesville, Virginia, in August 2017 and have clashed repeatedly with far-right groups in Portland, Oregon, including at a protest and counter-demonstration last summer that resulted in arrests and the seizure of shields, poles and other weapons.
WHAT ROLE IS ANTIFA PLAYING IN THESE DEMONSTRATIONS?
Trump and members of his administration have singled out Antifa as being responsible for the violence at protests triggered by the killing of George Floyd, a black man who died after a white Minneapolis police officer pressed his knee into his neck for several minutes even after Floyd stopped moving and pleading for air.
In a pair of statements over the weekend, Attorney General William Barr described "Antifa-like tactics" by out-of-state agitators and said Antifa was instigating violence and engaging in "domestic terrorism" and would be dealt with accordingly.
At a White House appearance Monday, Trump blamed Antifa by name for the violence, along with violent mobs, arsonists and looters.
White House press secretary Kayleigh McEnany told reporters earlier in the day that Antifa is a "big element of this protest," though she deferred to the Justice Department on the question of how one could be identified as a member.
But it's unclear how big its involvement is.
Bray said that although he believes people associated with Antifa are participating in the demonstrations, it is difficult to establish how big of a role they're playing since there is no official roster of members and since the movement lacks the numbers to mobilize nationwide in such a dramatic, forceful way.