PORTLAND, Ore. (AP) — A federal judge in Oregon on Monday restricted federal officers from using tear gas at protests at the U.S. Immigration and Customs Enforcement building in Portland, in response to a lawsuit filed by the ACLU of Oregon on behalf of protesters and freelance journalists.

U.S. District Judge Michael Simon issued the preliminary injunction after a three-day hearing in which the plaintiffs — including a demonstrator known for wearing a chicken costume, a married couple in their 80s and two freelance journalists — testified about having chemical or projectile munitions used against them.

The lawsuit, whose defendants include the Department of Homeland Security, argues that federal officers’ use of such munitions is a retaliation against protesters that chills their First Amendment rights.

“Plaintiffs provided numerous videos, which were received in evidence and unambiguously show DHS officers spraying OC Spray directly into the faces of peaceful and nonviolent protesters engaged in, at most, passive resistance and discharging tear gas and firing pepper-ball munitions into crowds of peaceful and nonviolent protestors,” Simon wrote, using the term OC Spray to refer to pepper spray.

“Defendants’ conduct — physically harming protestors and journalists without prior dispersal warnings — is objectively chilling.”

DHS did not immediately respond to a request for comment. In previous statements, it said federal officers followed their training and used the minimum amount of force necessary.

Simon had previously issued a temporary restraining order similarly limiting federal agents from using chemical munitions during protests at the ICE building. His preliminary injunction is the second in recent days restricting agents’ tear gas use at the facility, following that of a federal judge overseeing a separate case brought by the residents of an adjacent affordable housing complex.

Federal officers’ aggressive crowd-control tactics are causing concern as demonstrators in cities across the country have protested the immigration enforcement surge spearheaded by President Donald Trump’s administration.

In his Monday order, Simon limited federal agents from using chemical or projectile munitions such as pepper balls and tear gas unless someone poses an imminent threat of physical harm. He also ordered agents not to fire munitions at the head, neck or torso “unless the officer is legally justified in using deadly force against that person.”

Additionally, officers cannot use pepper spray against a group in an indiscriminate way that would affect bystanders; they must only target people who are engaging in violent unlawful conduct or actively resisting arrest, or use it “as reasonably necessary in a defensive capacity,” Simon wrote. He specified that trespassing, refusing to move and refusing to obey an order to disperse are acts of passive, not active, resistance.

Simon also granted provisional class certification, which means his order covers a broader group of all those who have peacefully protested or reported on demonstrations at the ICE building in recent months.

The preliminary injunction will remain in effect while the lawsuit proceeds.