WASHINGTON

California Gov. Gavin Newsom dug in Monday as President Donald Trump escalated his threats and called for his arrest amid a spiraling row over immigration protests in Los Angeles sparked by sweeping federal round-ups.

"It’s just an extraordinary moment, and I don’t want to overstate it, but these are the words of an authoritarian,” Newsom said during an interview with the Politico news outlet. “Whether he acts on it or not, the chill that creates is real, and it’s a serious moment, very serious.”

The comments come after Trump's border tsar, Tom Homan, threatened Newsom and Los Angeles Mayor Karen Bass with arrest over the ongoing civil unrest sparked by the Trump's administration's immigration raids. Newsom responded by daring the senior official to follow through on the threat.

Trump endorsed the idea of arresting Newsom when asked by reporters after returning to the White House from Camp David on Monday.

"I'd do it if I were Tom (Homan). I think it’s great," he said.

Trump is known for urging law enforcement and prosecutors to target his political opponents and “lock them up,” a chant he has encouraged among his followers, but directly endorsing the arrest of a sitting governor appears to be a first.

"The President of the United States just called for the arrest of a sitting Governor. This is a day I hoped I would never see in America. I don’t care if you’re a Democrat or a Republican, this is a line we cannot cross as a nation — this is an unmistakable step toward authoritarianism," Newsom responded on X.

Asked what crime Newsom committed that would warrant the highly irregular arrest of a state leader, Trump said: " I think his primary crime is running for governor because he's done such a bad job."

"What he's done to that state is like what (former President Joe) Biden did to this country, and that's pretty bad; it's the wrong philosophy. Hundreds of thousands of illegal immigrants, many of them prisoners, are taking up your health care. They are taking up your space in schools. They are taking up your hospital. And in many cases, they are criminals. And we have to do something about it," Trump told reporters.

Reports on Monday suggest the president is preparing to deploy hundreds of Marines to Los Angeles to augment the National Guard troops currently there. CNN reported that over 700 troops based out of the Marine Corps Air Ground Combat Center in California have already been mobilized.

“He is unhinged, and he’s acting recklessly, and the threat of the Marines coming in the United States, this is a very serious and sober moment. We are going to stand firm,” Newsom said during the interview with Politico.

When asked about sending combat troops to America's second largest city, Trump demurred, saying, "We'll see what happens. I mean, I think we have it very well under control."

On Saturday, Trump signed a memo invoking his authority to deploy a minimum of 2,000 National Guard troops to Los Angeles County after confrontations between immigration officers and protesters as well as widespread demonstrations.

Critics of Trump's immigration raids say Immigration and Customs Enforcement (ICE) is going after law-abiding undocumented migrants, a vital part of the community and the local economy, rather than the criminals that Trump pledged to deport while campaigning last year to return to the White House.