U.S. military troops and federal immigration officers made a brief but mighty show of force Monday at a Los Angeles park in a neighborhood dubbed the “Ellis Island of the West Coast" for its large immigrant population.

Federal officials said it was an immigration enforcement operation, though it was unclear if anyone had been arrested. “It’s the way a city looks before a coup,” Mayor Karen Bass said as she condemned the action.

Dozens of immigration agents, some on horseback, others carrying rifles in armored vehicles, swept through MacArthur Park.