Facebook on Friday said it has removed accounts of far-right group Patriot Prayer for violating its ban on dangerous groups or individuals.
"They were removed as part of our ongoing efforts to remove violent social militias from our platform," Facebook said in response to an AFP query.
Patriot Prayer has become embroiled in recent violence pitting rival groups of protesters against one another in the north-western city of Portland, and a follower of the group was fatally shot last weekend.
Patriot Prayer is a far-right group active in the Pacific north-west, according to the Southern Poverty Law Center.
"Over the past three years, the group has hosted and promoted rallies in progressive cities like Portland, frequently engaging in violence against their political opponents," the centre said in a post on its website.
"Patriot Prayer rallies regularly include the Proud Boys, a hate group, and various antigovernment extremist groups."
Media in Oregon cited an attorney for Patriot Prayer founder Joey Gibson as confirming that his accounts and those of the group were removed by Facebook.
Mr Gibson has rejected accusations that Patriot Prayer is a white supremacist group, maintaining it is a Christian organisation, according to local media.
Shootings at protests against police brutality have stoked fears of rising violence as a deeply divided US heads into elections amid economic collapse, the pandemic and the worst social upheaval since the 1960s.
"The radical right is actively looking to exploit today's historically polarised political climate - one that has become even more uncertain under the strain of the coronavirus pandemic and protests for racial justice," warned the Southern Poverty Law Center, which tracks extremist groups.
"With the 2020 presidential election fast approaching, the prospect that extremists might resort to political violence is a very real one," it said.
Up against the extreme right is a more diverse coalition of activists that US President Donald Mr Trump collectively calls "Antifa," short for "Anti-fascist," whom he accuses of being "rioters, anarchists, agitators and looters."
Its members "vary from thugs who like to fight... to those who are more truly defensive to those who are active on social media, trying to dox white supremacists," said Daniel Byman of the Brookings Institution.
Facebook last month removed hundreds of groups tied to the far-right QAnon conspiracy theory and imposed restrictions on nearly 2,000 more as part of a crackdown on stoking violence.
The platform has seen growth in movements that celebrate violence or weapons and hint at using them but stop short of directly organising any action, Facebook said.
Facebook last week removed accounts of a teenager accused of a deadly shooting spree during protests in the US city of Kenosha, along with pages of a local militia.
Facebook also removed a Kenosha Guard page and an event page posted by the militia group for violating a recently instituted ban on groups that celebrate violent acts or suggest that people seek armed conflict.
