CHICAGO (AP) — As encounters with federal immigration agents around Chicago increase, tactics used by activists and immigrant leaders to fight back are also escalating.

The Trump administration has singled out Chicago as its latest mark for immigration enforcement, using traffic stops in immigrant-heavy areas and targeting day laborers outside hardware stores.

“We will not back down,” Homeland Security Secretary Kristi Noem posted Thursday on X, recirculating dramatic footage of arrests at a suburban Chicago home days earlier.

Activists and local leaders are also defiant, trying to deter agents, warn residents and keep attention on a man killed by an immigration officer last week.

As U.S. Immigration and Customs Enforcement launched a new operation this month, the focus appeared to be on traffic stops in largely immigrant and Latino neighborhoods and suburbs. This week, activists say arrests of day laborers are also on the rise, echoing what immigration agents have done elsewhere.

Federal agents were spotted at roughly half a dozen Home Depot and Menards stores in the city and suburbs resulting in individual arrests, according to activists.

“Our neighbors who build, paint, fix and beautify this city have been the target of these unwarranted attacks,” said Miguel Alvelo Rivera with the Latino Union, which advocates for day laborers.

He spoke Thursday near a Home Depot in the heavily Latino and immigrant Brighton Park neighborhood where ICE agents were spotted a day earlier. The Chicago area has roughly 300 such workers, according to the Latino Union.

In immigrant and activist circles, the arrests are commonly referred to as abductions because many agents wear masks, drive unmarked vehicles and don’t have insignia on their clothes.

Giselle Maldonado, 23, said two of her uncles — Gabriel Soto-Rivera, 40, and Eder Nicolas Jimenez Barrios, 37 — were detained Monday by ICE on Chicago’s west side as they were driving to work as HVAC technicians. Her uncles have since told other family members that they believed they were being pulled over for a routine traffic stop.

Maldonado found out her uncles had been detained when her mother sent her videos of the encounter posted to TikTok. In the videos, an agent wearing a vest with the words “Police Federal Agent” can be seen speaking to someone in a vehicle.

Maldonado said she immediately thought of Gabriel’s two young children.

“Who’s going to be there for them?” she said. “They’re babies.”

Known for organizing, Chicago’s activists have quickly dispatched volunteers to sightings of immigration agents. They record video and gather other information to notify the family of arrestees.

Activists circulate the license plates of suspected ICE vehicles on social media and take part in disruptive demonstrations outside hotels where agents are believed to be staying. Bike patrols look out for agents, while some follow vehicles on foot and yell to warn those in the vicinity.

One neighborhood on Chicago’s southwest side is making a lot of noise, literally.

When word of increased enforcement in Chicago ramped up, Baltazar Enriquez started buying orange emergency whistles so people could warn others of nearby ICE agents. He said they are reliable even when technology fails.

“If they hear that sound, they immediately start closing their doors, locking their gates,” he said of neighbors. “This has worked for us here. People are asking us, ‘Can I get a whistle?’ “