Updated at 3:35 p.m. with condemnation from Dallas Mayor Mike Rawlings, ACLU and others.

WASHINGTON — The Trump administration's chief immigration enforcer wants to prosecute the elected leaders of cities that limit cooperation with his agency -- a threat that drew shrugs Wednesday from Dallas City Hall and condemnation from civil rights groups.

"We need to hold these politicians accountable for their actions," Thomas Homan, acting director of Immigration and Customs Enforcement, told Fox News. "This isn't the America I grew up in. We got to take these sanctuary cities on. We got to take them to court. And we got to start charging some of these politicians with crimes."

Homan insisted that President Donald Trump shares his view. Such a policy would dramatically raise the stakes for immigrant-friendly cities and states that have clashed with the administration. Critics denounced the intimidation tactic, insisting it would never fly in court.

"It's total hogwash," said Dallas Mayor Mike Rawlings, saying he has "zero fear" of being arrested, in part because he takes issue with assertions that Dallas unlawfully shields immigrants from federal authorities. "No one is going to be arrested, especially here in Dallas. We're not a sanctuary city. We cooperate with ICE. This is basically rattling a saber to make good sound bites."

The ACLU said Homan's "outrageous threat" should disqualify him from leadership of the agency that enforces immigration law. He has served as acting chief of ICE for nearly a year, replacing former Dallas-based U.S. attorney Sarah Saldaña, an Obama appointee who resigned shortly after Trump's inauguration. Trump nominated him for the job on a permanent basis in November.

A number of Texas cities, including Dallas, Houston, San Antonio and Austin — all led by Democrats — have resisted the president's hardline approach to immigration, prompting a state law aimed at pressuring local jurisdictions.

Leaders in those cities would presumably be targeted under Homan's approach.

Houston Police Chief Art Acevedo told the Houston Chronicle that the threat smacked of an attempt to trample on "states' rights and local rights."

Austin Mayor Steve Adler vowed to continue to "oppose anti-immigrant policies, regardless of the personal consequences.... Threatening to jail political opponents, especially for laws they aren't breaking, is not the America I grew up in."

At the ACLU, deputy legal director Cecillia Wang said that "multiple courts have ruled that the Constitution or federal law prohibits the Trump administration's efforts to intimidate states and localities into participating in draconian immigration enforcement tactics." She called it "outrageous" for Homan to threaten "to prosecute state and local government officials for carrying out lawful sanctuary policies."

Texas law

Last year, Texas enacted a ban on sanctuary cities, making it a crime for police chiefs, county sheriffs and constables to prohibit their officers from aiding federal immigration authorities. The law also allows for the removal of officials who violate the ban, and would penalize jurisdictions up to $25,000 for each day it is violated.

The ban, which allows all police officers in Texas to inquire about immigration status during routine stops, is being challenged in federal court. A federal judge in San Antonio blocked implementation of most of the law, but the state has challenged that ruling. The 5th Circuit Court of Appeals is considering the matter.

In a visit to Austin in October, Attorney General Jeff Sessions praised Texas for passing the law and vowed to help defend it in court.

Thomas Saenz, president of the Mexican American Legal Defense and Educational Fund, which represents the plaintiffs in the Texas suit, also denounced Homan's threat, insisting there is nothing unconstitutional about the policies in California or elsewhere.

"Elected officials are held accountable by voters, not mid-level acting ICE officials," Saenz said. "This is just about threatening and intimidating folks. Totalitarian thugs have no place in our government and Homan needs to go."

Saenz said the Obama administration never threatened to prosecute local officials for enacting laws it found unconstitutional, like SB 1070, Arizona's "papers, please" law. Instead, it joined organizations like MALDEF and fought them in court.

He said it was ironic that the Trump administration is now threatening to arrest local officials who have not committed a crime, when it pardoned Maricopa County Sheriff Joe Arpaio, the only local official prosecuted in the dispute over SB 1070 for repeatedly flouting a court's decision.

"We're going to enforce the law without apology," Homan said Tuesday in an interview with Fox's Neil Cavuto that focused mainly on resistance to federal immigration enforcement by California cities and Gov. Jerry Brown.

Trump issued an executive order in his first week as president aimed at pressuring so-called sanctuary cities, though the order was quickly blocked in court.

In August 2015, in the early days of the 2016 GOP presidential contest, Bobby Jindal, then governor of Louisiana, said he would "absolutely" view any mayor or local official in a so-called sanctuary city as an "accomplice" to crimes committed by people in the country illegally, and would seek prosecution.

No legal definition

One of the challenges with cracking down on sanctuary cities is that there is no legal definition for the term. While Trump administration officials have promised to bring down the hammer, they've struggled to explain just what would lead to punishment, sowing confusion among local officials, including Rawlings, the Dallas mayor.

Tuesday, Homan offered a new criterion: a statute aimed at human smuggling.

"For these sanctuary cities that knowingly shield and harbor an illegal alien in their jail and don't allow us access, that is, in my opinion, a violation of 8-USC-1324. That's an alien smuggling statute," he said. "I have asked the Department of Justice to look at this. ... That's certainly an angle we're looking at."

The statute Homan cited makes it an offense for any person "to conceal, harbor, or shield from detection, such alien in any place, including any building or any means of transportation."

Although a number of Texas cities have resisted Trump's moves on immigration, leadership at the state level has been far more in line with the White House agenda. Gov. Greg Abbott has sought to pressure sanctuary cities, and signed the law being fought over in court. State Attorney General Ken Paxton has enthusiastically defended the law.

The political dynamic is much different in California. In October, Brown — a Democrat — signed a "sanctuary state" law in an effort to stymie Trump's push to intensify enforcement by limiting the flexibility for local law enforcement to cooperate with federal immigration authorities. The state has an estimated 2 million unauthorized immigrants.

Sessions has called the California law "unconscionable." On Tuesday, Homan was combative in vowing to circumvent Brown's tactics.

"If he thinks ICE is going away, we're not," he said. "There's no sanctuary from federal law enforcement. ... I'm going to significantly increase our enforcement presence in California. We're already doing it. We're going to detail additional enforcement assets to California. California better hold on tight. They're about to see a lot more special agents, a lot more deportation officers in the state of California. If the politicians in California don't want to protect their communities, then ICE will."

In Dallas, Rawlings said the tough talk doesn't faze him, and he won't tweet at Homan or "call him Mr. ICE man or something."

"We're a country of laws, we're a country of courts and that's why folks speak their minds and do what's right," the mayor said. "I'm sure the legal world will protect cities and jurisdictions to do what's right. What's happening in California is a totally different situation. We, as a city, have never voted to do anything that's contrary to ICE."

Staff writer Tristan Hallman in Dallas contributed to this report.