The suit, filed Monday by Wall of Moms, Don't Shoot Portland and a number of individuals, alleges that federal agents have used violence to "stamp out peaceful and constitutionally protected protests" and that their mere presence as a federal domestic security force is unconstitutional.
This month, President Donald Trump sent federal agents to Portland as protests continue after the death of George Floyd in police custody.
The suit alleges that federal agents -- some of whom "are not trained to police mass protests protected by the first amendment" -- have been used to quell demonstrations and "betray a foundational principle of American Democracy."
The US Marshals Service, US Department of Justice, Federal Protective Service, US Immigration and Customs Enforcement, US Customs and Border Protection and US Department of Homeland Security are among the defendants listed in the lawsuit that claims more than 100 agents were sent to the city under "a policy to intimidate and deter protesters because of their views and beliefs."
CNN has reached out to the Department of Homeland Security, which the Federal Protective Service is under, and the US Marshals Service for response.
Wall of Moms, Don't Shoot Portland and other protesters have been subject to tear-gassing, unlawful arrests without probable cause and shootings with rubber bullets and bean bags at close range by DHS agents donning military fatigues and gear, repeatedly resulting in injury, the lawsuit said. The tear gas has left some vomiting and unable to eat or sleep, according to the suit.
"They have been forced to speak and assemble in fear of not just bodily harm, but the possibility of sudden arrest without probable cause," the suit said.
Portland mayor demands 'cease-fire'
Videos have emerged showing authorities without identification badges in unmarked vehicles arresting protesters in Portland. These incidents have sparked the state's US attorney to call for an investigation into the matter.
Federal involvement in protest response has not been welcomed by local leaders.
In a Monday night tweet, Portland Mayor Ted Wheeler called for an immediate meeting with DHS leadership "to discuss a cease-fire and the removal of heightened federal forces."
Last week, a unanimous Portland City Council voted to end cooperation between the Portland Police Bureau and federal agencies.
Wheeler has come under intense scrutiny by Trump and acting DHS secretary Chad Wolf after weeks of protests in his city.
Ahead of the July Fourth weekend, the Trump administration dispatched teams of federal agents to the city -- the President said the effort was to protect federal property but protesters say the action itself has fueled the public's outrage.
For several nights, largely peaceful protests demanding racial justice and an end to an influx in federal resources in the city, have turned violent as a small subset of rioters have set fires and launched fireworks at the city's downtown federal cour
