A man armed with an assault rifle protests in Salem, Oregon, against the state’s economic closures in the wake of the coronavirus. Picture: Getty Images

A mask with a message: a demonstrator protests the death of unarmed black man George Floyd, who died in police custody in Minneapolis in May. Picture: AP

In 2016 a small group of armed activists occupied the Malheur National Wildlife Refuge in Oregon for more than a month, demanding the federal government turn over land they managed to the states. Picture: AFP

Armed protesters take part in an American Patriot Rally in Michigan in April, demanding the reopening of businesses. Picture: AFP

Demonstrators in Lansing, Michigan, protest the stay-at-home orders. Picture: AFP

Protesters from the militant, left-wing, anti-fascist political activist movement Antifa protest in Portland, Oregon, to oppose the right wing group The Patriot Prayer Movement in 2017. Picture: AFP

A protester is detained by police in New York City following the death of George Floyd. Picture: Getty Images

A police officer stands with a baton as a fire burns near the Third Police Precinct in Minneapolis, Minnesota. Businesses have been looted and damaged during ongoing protests following the death of George Floyd. Picture: Getty Images

Protestors attempt to enter the Michigan House of Representatives in April, demanding the reopening of businesses. Picture: AFP

Law enforcement officers watch on as people protest for the third straight day following the death of George Floyd. Picture: AFP

Armed protesters demonstrate during the Michigan Conservative Coalition-organised ‘Operation Haircut’ in May this year, protesing Michigan Governor Gretchen Whitmer’s mandatory closure to curtail the coronavirus pandemic. Picture: AFP

Barbers and stylists offered free haircuts as part of the Operation Haircut rally. Picture: AFP

Demonstrators gather at the American Patriot Rally in Michigan. The group describes itself as a “movement dedicated to protecting America’s freedom for all future generations.” Picture: AFP

Armed protesters at the American Patriot Rally. Picture: AFP

Abraham Eddy of Lapeer was one of eleven Eddy children protesting Governor Whitmer’s stay-at-home order in Michigan. Picture: AP

A local militia group protest the stay-at-home order in Columbus, Ohio, in April. Picture: AFP

A screenshot from a video by Neo-Nazi group Atomwaffen Division as they train outside Seattle.

Armed groups of private citizens have increasingly been taking on a security function at public events where the possibility of violent protest exists, including at the recent Unite the Right rally in Charlottesville, Virginia. Picture: Reuters