Federal officers clad in tactical gear deployed smoke, tear gas, flash grenades and other projectiles as the restive crowd of demonstrators hurled water bottles and fireworks in return.

Thousands of people nationwide have shown up at demonstrations and rallies opposing Immigration and Customs Enforcement raids.

The protests that put Los Angeles at the center of a standoff with the president began late last week, just after federal immigration agents reportedly rounded up dozens of people in the city’s Fashi...