LOS ANGELES — Homeland Security Secretary Kristi Noem pledged Thursday to carry on with the Trump administration’s immigration crackdown despite waves of unrest across the U.S., while in Texas thousands of National Guard troops were on standby in case more trouble breaks out.

The moves unfolded as cities nationwide braced for major demonstrations against President Donald Trump over the weekend, and their leaders pleaded with residents to protest peacefully.

Noem said the immigration raids that fueled the protests will move forward, saying agents have thousands of targets.

“This is only going to continue until we have peace on the streets of Los Angeles,” she said during a news conference that was interrupted by shouting from U.S. Sen. Alex Padilla, a California Democrat who was forcibly removed from the event.

Noem spoke hours before President Donald Trump’s use of troops to help carry out immigration raids faced its biggest challenge yet as a federal judge began weighing a request from California Gov. Gavin Newsom to put an emergency stop to the practice.

Newsom has warned that the military intervention is part of a broader effort by Trump to overturn norms at the heart of the nation’s democracy. He also said that sending National Guard troops on the raids has further inflamed tensions in Los Angeles, where large and sometimes volatile protests have broken out since the crackdown began nearly a week ago.

So far, the protests have been centered mostly in downtown LA near City Hall and a federal detention center where some immigrants are being held. Much of the sprawling city has been spared from the protests.

The Trump administration on Wednesday called Newsom’s lawsuit a “crass political stunt endangering American lives.”

The court hearing Thursday in San Francisco opened with Senior U.S. District Court Judge Charles R. Breyer asking attorneys whether Trump followed the law when he called in the National Guard.

“We’re talking about the president exercising his authority, and the president is, of course, limited in that authority,” Breyer said. “That’s the difference between a constitutional government and King George.”

The judge added: “This country was founded in response to a monarch, and the constitution is a document of limitations. I’m trying to figure out where the lines are drawn.”

Demonstrations have picked up across the U.S., with protests emerging in more than a dozen major cities. On Wednesday, police in Seattle used pepper spray to clear out protesters, and officers in Denver used smoke and pepper balls to control a crowd.

Police in riot gear — many on horseback — charged at a group of protesters Wednesday night in LA just before the start of the second night of the city’s downtown curfew. The officers struck some demonstrators with wooden rods and later fired crowd-control projectiles. After the curfew went into effect, a handful of arrests were made before the area cleared out.

The immigration agents conducting the raids in LA are “putting together a model and a blueprint” for other communities, Noem said.

She pledged that federal authorities “are not going away,” even though, she said, officers have been hit with rocks and bricks and assaulted. She said people with criminal records who are in the country illegally and violent protesters will “face consequences.”

“Just because you think you’re here as a citizen, or because you’re a member of a certain group or you’re not a citizen, it doesn’t mean that you’re going to be protected and not face consequences from the laws that this country stands for,” she said.

Noem criticized the California senator’s interruption, calling it “inappropriate.” A statement from her agency said Noem and Padilla met after the news conference for about 15 minutes, but it also chided him for “disrespectful political theater.”

Padilla said later that he was demanding answers about the “increasingly extreme immigration enforcement actions” and only wanted to ask Noem a question. He said he was handcuffed but not arrested.

“If this is how this administration responds to a senator with a question, I can only imagine what they are doing to farm workers, to cooks, to day laborers throughout the Los Angeles community,” he said.

The Trump administration has rapidly expanded military deployments to Los Angeles over the past week and has said it is willing to send troops to other cities to assist with immigration enforcement and controlling disturbances — in line with what Trump promised during last year’s campaign.