The streets of Los Angeles rang with the sound of flash-bang grenades on Friday, as camouflage-clad federal agents rolled through the garment district in search of workers who they suspected of being undocumented immigrants. They were met with protesters, who chanted and threw eggs before being dispersed with pepper spray and nonlethal bullets.

The enforcement operation turned into one of the most volatile scenes of President Trump’s immigration crackdown so far, but it was not an isolated incident.

Last week, at a student housing complex under construction in Tallahassee, Fla., masked immigration agents loaded dozens of migrants into buses headed to detention centers. In New Orleans, 15 people working on a flood control project were detained. And raids in San Diego and Massachusetts — in Martha’s Vineyard and the Berkshires — led to standoffs in recent days as bystanders angrily confronted federal agents who were taking workers into custody.

The high-profile raids appeared to mark a new phase of the Trump administration’s immigration crackdown, in which officials say they will increasingly focus on workplaces — taking aim at the reason millions of people have illegally crossed the border for decades. That is an expansion from plans early in the administration to prioritize detaining hardened criminals and later to focus on hundreds of international students.

“You’re going to see more work site enforcement than you’ve ever seen in the history of this nation,” Thomas D. Homan, the White House border czar told reporters recently. “We’re going to flood the zone.”