The FBI has asked agents from field offices across the United States to voluntarily travel to Minneapolis for temporary assignments as the city reels from anti-ICE protests and the fatal shooting of Renee Good, according to two sources.

The request was first reported by Bloomberg and confirmed by a law enforcement official familiar with the messages and another source familiar with the requests who has seen the messages.

The messages sent to agents and field offices were not clear about what the exact assignment would be for volunteers who do relocate. The second source told NBC News that the agents will investigate “AFO” cases — an FBI designation to identify and charge suspects accused of assault on a federal officer. Agents are also needed to investigate vandalism and theft of property from FBI vehicles, the second source added.

There has been a surge of federal immigration personnel in Minnesota, and protests have rocked the state in outrage over the Jan. 7 fatal shooting of Good in Minneapolis by an Immigration and Customs Enforcement officer.

At the moment, the request call is voluntary, and there’s not a mass surge of FBI agents to Minneapolis, the sources said. And so far, one source said, the response has been minimal.

A spokesperson for the FBI declined to comment.

The scale of the immigration enforcement presence in Minneapolis — with roughly 3,000 federal immigration officers — appears to be greater than in previous operations in blue cities such as Chicago and Los Angeles.

Residents have described the swell of officers as “an invasion,” with agents seen in unmarked cars idling on neighborhood streets, at stores and in parking lots and going door to door.

Local officials, including Mayor Jacob Frey, have called for ICE to leave the city. Meanwhile, President Donald Trump last week threatened to invoke the Insurrection Act in response to protesters, calling them “professional agitators and insurrectionists.”