The U.S. Justice Department has ordered federal prosecutors to provide examples of “unusual judicial system obstacles” they have faced during criminal or civil proceedings tied to immigration, assaults on law enforcement or “antifa,” according to a government email reviewed by Reuters.

The highly unusual request to collect examples of what the department sees as judicial pushback was sent on Thursday evening by a senior official in Deputy Attorney General Todd Blanche’s office to U.S. Attorneys.

It suggests an escalation in a series of confrontations between federal district courts and the Trump administration.

Trump and his allies have repeatedly called judges who have ruled against his administration “crooked,” “conflicted” and “rogue.” Many of the judges have been subjected to threats or harassment after issuing rulings against the Trump administration.

A Justice Department spokesperson, when asked on Friday to comment on the email, reiterated criticism of certain judges’ actions.

“Across the country, judicial activists – liberals in robes – continue to obstruct lawful efforts to protect the American people, even in cases where the Supreme Court has already made the law unmistakably clear,” the spokesperson said.

“The department is committed to strengthening our litigation posture at every level so we can better defend public safety initiatives and prevent activist judges from undermining the rule of law.”

In the email, Blanche’s office instructed each U.S. attorney’s office to provide two to three examples of judges posing challenges to Justice Department efforts to obtain search warrants or signatures on criminal complaints, get approval on jury instructions, or obtain pre-trial detention.

It asked prosecutors to focus on cases related to assaults against federal agents, particularly if they involved immigration enforcement or investigations into anti-fascist movement groups known as “antifa,” which the Trump administration has designated as a terrorist organization.

The email did not indicate what the Justice Department intends to do with the information, which prosecutors were asked to submit by midday on Friday.

The email comes shortly after Blanche appeared at an event hosted by the conservative Federalist Society, where he made fiery remarks about federal district court judges.

“They have a robe on but they are more political or certainly as political as the most liberal governor or D.A.,” Blanche said.

“There’s a group of judges that are repeat players, and that’s obviously not by happenstance, that’s intentional, and it’s a war, man.”

A group of 50 retired judges criticized his comments, saying his rhetoric “poses a grave threat to the rule of law and the judiciary.”

Federal judges across the country have increasingly raised concerns over the legality of Trump administration policies on matters ranging from immigration to the targeting of medical practitioners who provide gender-affirming care to transgender youth.

Chief U.S. District Court Judge James Boasberg earlier this year concluded the Trump administration appeared to have acted in bad faith when it hurriedly assembled three deportation flights on March 15 at the same time that he was conducting emergency court proceedings to assess the legality of the action.

Boasberg found probable cause to hold the government in criminal contempt and launched an investigation to determine who was responsible, but a federal appeals court later tossed out his ruling in a 2-1 decision.