The arrest of a high-profile union leader during ICE protests last week has prompted an outcry across labor organizations across the U.S., and could mark the beginning of a new escalation between organized labor and President Donald Trump in the war over immigration.

During a protest later that day outside of the Metropolitan Detention Center in downtown Los Angeles, the union says Huerta was serving as a community observer and documenting ICE activities when he was arrested by federal agents for allegedly interfering and blocking a law enforcement vehicle.