Protests against immigration raids in downtown Los Angeles Friday intensified into the evening – prompting authorities in riot gear to deploy tear gas and flash bangs to disperse crowds. Police on Friday night issued a citywide tactical alert nearly two hours after declaring protests across the downtown area unlawful assemblies.

A local immigrant rights organization said more than 45 people were detained in the operations, which were described as “random sweeps.”

The FBI confirmed it’s participating in the HSI raids, not just in Los Angeles but nationwide, “as directed by the Attorney General.”