WASHINGTON — The Justice Department has ordered federal prosecutors to investigate state or local officials who they believe are interfering with the Trump administration’s crackdown on immigration, saying they could face criminal charges, in an apparent warning to the dozens of so-called sanctuary jurisdictions across America.

The memo, written by acting Deputy Attorney General Emil Bove, also instructs the Justice Department’s civil division to work with a newly formed Sanctuary Cities Enforcement Working Group to identify state and local laws and policies that “threaten to impede” the Trump administration’s immigration efforts and potentially challenge them in court.

The memo signals a sharp turnabout in priorities from President Joe Biden’s Democratic administration, with prosecutors told in no uncertain terms that they will be on the front lines of an administration-wide effort to crack down on illegal immigration and border crime and that they are expected to carry out the policy vision of President Donald Trump’s Republican White House when it comes to violent crimes, the threat of international gangs and drug trafficking.

“Indeed, it is the responsibility of the Justice Department to defend the Constitution, and accordingly, to lawfully execute the policies that the American people elected President Trump to implement,” wrote Bove, who prior to joining the administration was part of the legal team that defended Trump against two criminal cases brought by the Justice Department.

“Sanctuary” has no legal definition, but the term encompasses a range of protection for immigrants, particularly those living in the U.S. illegally. Most often, the laws put legal limits on law enforcement in those jurisdictions about how they can cooperate with federal immigration authorities.

Courts have repeatedly upheld most sanctuary laws.

In Chicago, which has some of the strongest sanctuary protections nationwide, city leaders brushed off word of potential investigations. The nation’s third-largest city has been a sanctuary city for decades, limiting cooperation between police and federal immigration agents.

“If the federal government is going to investigate, that is their prerogative,” said Alderman Andre Vasqez, who is Mayor Brandon Johnson’s handpicked chair of the City Council immigration committee.

Vasquez, the son of two Guatemalan immigrants, noted a 2016 campaign rally at the University of Illinois Chicago that Trump abruptly scrapped as crowds of boisterous protesters grew. The cancellation remains a badge of honor for many young activists in the Democratic stronghold.

“There will always be that kind of relationship between Chicago, President Trump and the Republican Party,” said Vasquez. “I was born and raised in Chicago, in an immigrant family. It will take more than that to make me feel a little scared.”

Bove’s memo said federal prosecutors must “take all steps necessary to protect the public and secure the American border by removing illegal aliens from the country and prosecuting illegal aliens for crimes committed in U.S. jurisdiction.”

The memo suggests there will be a spike in immigration cases under the new administration, instructing U.S. attorney’s offices across the country to inform courts of its policy “and develop processes for handling the increased number of prosecutions that will result.” Any decisions by federal prosecutors to decline to prosecute immigration violations must be disclosed to Justice Department headquarters in so-called urgent reports, which are used to update leadership on law enforcement emergencies or significant matters of national interest.