LOS ANGELES -- Federal prosecutors are investigating Minnesota Governor Tim Walz and Minneapolis Mayor Jacob Frey for allegedly impeding federal law enforcement operations in the state, Fox News reported Friday.

The two officials' rhetoric against the United States Immigration and Customs Enforcement (ICE) was approaching a potential federal offense, US Deputy Attorney General Todd Blanche was quoted as saying.

"When the governor or the mayor threatens our officers, when the mayor suggests that he's encouraging citizens to call 911 when they see ICE officers, that is very close to a federal crime," Blanche said.

Two sources familiar with the matter confirmed that a probe is underway, though it remains in its early stages and it is unclear if it will result in criminal charges, said the report. No further details have been released publicly.

The Hill, a US political website, reported that the Department of Justice (DOJ) on Friday issued subpoenas for the two Democratic Party politicians, accusing them of interfering with federal law enforcement officers' ability to carry out their duties.

In a statement in response to the DOJ investigation, Walz said: "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," the governor said.

The investigation came amid heightened tensions following a federal immigration crackdown in Minnesota. On Jan 7, Good, a 37-year-old US citizen, was fatally shot by ICE agent Jonathan Ross during an enforcement operation in Minneapolis, a major city in Minnesota.

Good's death sparked nationwide protests last weekend. Frey and Walz have since called on ICE to end its raids in Minneapolis and St. Paul, where about 2,500 people have been arrested as of Friday.