Federal agents tossed tear gas canisters, released pepper spray and fired pepper balls at protesters, journalists and other observers during an operation Friday at a taco shop on the west side of Tucson, Arizona.

Agents were trying to disperse a crowd outside the shop's parking lot. The taqueria was one of several sites that federal officers had searched as part of an investigation into immigration and tax violations, officials from U.S. Immigration and Customs Enforcement told the Arizona Daily Star. The newspaper reported that a neighbor saw agents arrest restaurant workers who lived near the taco shop.

In a statement, Tucson’s mayor and vice mayor called the federal agents’ use of force “disproportionate” and said it “was not justified and cannot be tolerated.”

U.S. Rep. Adelita Grijalva, a Democrat who was sworn into Congress only weeks ago and whose district includes the neighborhood, said she was pepper-sprayed in the face as she watched federal agents.

"There has to be some regulation. They have to follow the law. They don't have to follow any laws at this point," Grijalva told The Marshall Project.

Officers with Homeland Security Investigations, a unit within ICE, detained two protesters in the back of a van. ICE officials would not answer questions at the scene, and the identities of those detained and the outcome of their cases were not clear Friday evening.

The incident illustrated the complicated relationship between local police and federal immigration authorities. Despite local officials’ concerns about the feds’ use of force, Tucson police arrived to block traffic and control the crowd so that the federal agents could eventually leave.