A new U.S. Department of Justice order targeting sanctuary jurisdictions has put the spotlight anew on Denver’s mayor, who has publicly vowed to resist the new president’s mass deportation campaign and has also threatened a lawsuit if the White House sends agents to schools and churches.  

In the Jan. 21 memo, Deputy Attorney General Emil Bove ordered federal prosecutors to investigate state and local officials who they believe are refusing to comply with the Trump administration’s federal immigration enforcement efforts.

The memo said federal laws prohibit state and local actors from “resisting, obstructing, and otherwise failing to comply with lawful immigration-related commands and requests” and directs federal litigating offices to investigate “incidents involving any such misconduct for potential prosecution.”

Bove also instructed the DOJ’s civil division to identify state and local laws and policies that “threaten to impede” the president’s immigration policies and potentially challenge them in court.

In a statement, Denver Mayor Mike Johnston said his administration will not obstruct federal law enforcement but added that the city police are not immigration officers.

“Denver does not obstruct federal law enforcement and has been clear that we will cooperate with ICE on violent criminals, as we always have,” Johnston said in a statement to The Denver Gazette. “However, our values and laws are clear. Local police do not do the work of immigration enforcement, and we will not be bullied into doing ICE’s job for them.”

Johnston is already on the Trump administration’s radar after vowing to repudiate the president’s plan to execute the largest mass deportation in U.S. history and saying he would deploy the city’s police forces at the county line to keep out federal forces.

After somewhat walking back that statement, Johnston said he is preparing the city for “all eventualities,” including losing millions in federal funds, over his public objections to the president’s immigration plans.

This week, the mayor said the city will sue the Trump administration if federal agents start raiding churches and schools. 

“What we can do is we can take them to court if they do come for those sites,” Johnston said. 

Colorado Attorney General Phil Weiser said he knows of no state or local officials obstructing immigration enforcement.

While no legal definition of a “sanctuary” city or state exists, broadly speaking it refers to a local jurisdiction that expressly refuses to cooperate with federal authorities on enforcing immigration laws.

Both Colorado and Denver have approved statutes that fall under that broad definition.

The Associated Press contributed to this story.