LOS ANGELES — Police swiftly enforced a curfew in downtown Los Angeles, making arrests moments after it took effect, while deploying officers on horseback and using crowd-control projectiles to break up a group of hundreds demonstrating against President Donald Trump’s immigration crackdown.

Members of the National Guard stood watch behind plastic shields but did not appear to participate in the arrests Tuesday night.

Hours later, many of the protesters had dispersed, although sporadic confrontations continued that were much smaller than in previous nights. Officials said the curfew was necessary to stop vandalism and theft by agitators looking to cause trouble.

The demonstrations have been mostly concentrated downtown, and the curfew covers a 1-square-mile (2.5-square-kilometer) section that includes an area where protests have occurred since Friday in the sprawling city of 4 million. The city of Los Angeles encompasses roughly 500 square miles (1,295 square kilometers).

Governor Challenges Military Deployment

Democratic Gov. Gavin Newsom earlier accused Trump of drawing a “military dragnet” across the nation’s second-largest city with his escalating use of the National Guard. He also deployed Marines, though none were seen on the streets Tuesday.

Newsom asked a court to put an emergency stop to the military helping federal immigration agents. The assistance includes some guardsmen now standing protectively around agents as they carry out arrests. The governor said the military presence would only heighten tensions and civil unrest. A judge set a hearing for Thursday, giving the administration several days to continue its activities.

The change moves the military closer to engaging in law enforcement actions such as deportations, as Trump has promised as part of his immigration crackdown. The Guard has the authority to temporarily detain people who attack officers, but any arrests would be made by law enforcement.

Trump has activated more than 4,000 National Guard members and 700 Marines over the objections of city and state leaders. They were originally deployed to protect federal buildings.

The president posted on the Truth Social platform that the city “would be burning to the ground” if he had not sent in the military.

Protests Spread Nationwide

Demonstrations have spread to other cities nationwide, including Dallas and Austin in Texas, and Chicago and New York, where thousands rallied and multiple arrests were made.

New York City police said they took 86 people into custody during protests in lower Manhattan Tuesday evening into Wednesday morning. Police Commissioner Jessica Tisch said the vast majority of demonstrators were peaceful.

In Texas, where police in Austin used chemical irritants to disperse several hundred demonstrators Monday, Republican Gov. Greg Abbott’s office said Texas National Guard troops were “on standby” in areas where demonstrations are planned, Abbott spokesperson Andrew Mahaleris said Tuesday evening.

Guard members were sent to San Antonio, but Police Chief William McManus said he had not been told how many troops were deployed or their role ahead of planned protests Wednesday night and Saturday.

LA Mayor Puts Curfew in Place

Los Angeles Mayor Karen Bass declared a local emergency on the fifth day of protests and said the curfew would run from 8 p.m. until 6 a.m. She expected it to last for several days.

“We reached a tipping point” after 23 businesses were looted, Bass said Tuesday.

The curfew doesn’t apply to residents who live in the designated area, people who are homeless, credentialed media or public safety and emergency officials, Police Chief Jim McDonnell said.

He said “unlawful and dangerous behavior” had been escalating since Saturday and that the curfew was needed to protect lives and property.

Trump left open the possibility of invoking the Insurrection Act, which authorizes the president to deploy military forces inside the U.S. to suppress rebellion or domestic violence or to enforce the law in certain situations. It’s one of the most extreme emergency powers available to a U.S. president.

“If there’s an insurrection, I would certainly invoke it. We’ll see,” he said from the Oval Office.

Later the president called protesters “animals” and “a foreign enemy” in a speech at Fort Bragg.

Trump has described Los Angeles in dire terms that Bass and Newsom say are nowhere close to the truth.

In a public address Tuesday evening, Newsom called Trump’s actions the start of an “assault” on democracy.

“California may be first, but it clearly will not end here. Other states are next,” he said.

Newsom warned people against inciting violence, but urged them to stand up to the president’s actions.

The protests began Friday after federal immigration raids arrested dozens of workers in Los Angeles. Protesters blocked a major freeway and set cars on fire over the weekend, and police responded with tear gas, rubber bullets and flash-bang grenades.

Thousands of people have peacefully rallied outside City Hall and hundreds more protested outside a federal complex that includes a detention center where some immigrants are being held following workplace raids.

Despite the protests, immigration enforcement activity has continued throughout the county, with city leaders and community groups reporting U.S. Immigration and Customs Enforcement present at libraries, car washes and Home Depots. School graduations in Los Angeles have increased security over fears of ICE action, and some have offered parents the option to watch on Zoom.

Los Angeles police made 197 arrests on Tuesday, including 67 who were taken into custody for unlawfully occupying a freeway, according to the city’s chief.

The majority of arrests since the protests began have been for failing to disperse, while a few others were for assault with a deadly weapon, looting, vandalism and attempted murder for tossing a Molotov cocktail. At least seven police officers have been injured.

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This story has been updated to show the metric conversion for the size of Los Angeles is 1,295 square kilometers, not 2,300.

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Baldor and Copp reported from Washington, D.C. Associated Press writers Dorany Pineda and Christopher Weber in Los Angeles, Amy Taxin in Orange County, California, John Seewer in Toledo, Ohio, Jim Vertuno in Austin, Texas, Hallie Golden in Seattle, and Greg Bull in Seal Beach, California, contributed to this report.