The Justice Department is investigating Minnesota officials, including Gov. Tim Walz and Minneapolis Mayor Jacob Frey, over an alleged conspiracy to impede federal immigration agents, an extraordinary escalation in the Trump administration’s clash with Democratic leaders there, multiple sources familiar with the matter told CBS News.

One of the sources, a U.S. official, said the investigation stems from statements that Walz and Frey have made about the thousands of Immigration and Customs Enforcement officers and Border Patrol agents deployed to the Minneapolis region in recent weeks.

A Justice Department spokesperson declined to comment.

Walz said in a statement: “Two days ago it was Elissa Slotkin. Last week it was Jerome Powell. Before that, Mark Kelly. Weaponizing the justice system and threatening political opponents is a dangerous, authoritarian tactic. The only person not being investigated for the shooting of Renee Good is the federal agent who shot her.”

 CBS News has also reached out to representatives for Frey.

Nearly 3,000 federal immigration agents have been dispatched to Minneapolis, with a stated objective of arresting people suspected of being in the U.S. illegally and probing allegations of fraud in Minnesota. The Department of Homeland Security has called the massive deployment the largest operation in its history.

The large-scale presence of federal agents has triggered widespread local backlash, sparking protests and clashes, especially after the killing of Minnesota resident Renee Good by an ICE officer last week.

Walz and Frey, both Democrats, have vocally denounced the federal deployment to the Twin Cities, accusing federal agents of creating chaos and undermining public safety through aggressive tactics.

Earlier this week, Frey said the federal deployment had created a situation that was “not sustainable.”

“We’re in a position right now where we have residents that are asking the very limited number of police officers that we have to fight ICE agents on the street,” Frey said. “We cannot be at a place right now in America where we have two governmental entities that are literally fighting one another.”

Walz and Frey have called for protests to remain peaceful. The governor urged Minnesotans not to “fan the flames of chaos” in a message on X Thursday.

Deputy Attorney General Todd Blanche appeared to make a vague reference to the investigation, writing on X earlier this week: “Walz and Frey- I’m focused on stopping YOU from your terrorism by whatever means necessary. This is not a threat. It’s a promise.”

Homeland Security Secretary Kristi Noem on Thursday said: “Mayor Frey and Governor Walz have to get their city under control. They are encouraging impeding and assault against our law enforcement which is a federal crime, a felony.”

Noem has said rhetoric from Walz and Frey “perpetuated” violence directed at federal officers, arguing their comments undermined public trust in law enforcement and emboldened protesters on the ground.

The federal inquiry is focused on a federal statute, 18 U.S.C. § 372, one U.S. official told CBS News, which makes it a crime for two or more people to conspire to prevent federal officers from carrying out their official duties through “force, intimidation or threats.”

The statute has historically been used in cases involving coordinated efforts to obstruct federal officials, including actions involving violence or threats. Public criticism of federal policy has historically been treated as protected speech unless involving direct coordination or incitement to obstruct law enforcement.