Following this shooting, the City of Minneapolis plans to request a temporary restraining order on Monday, urging a federal judge to stop ongoing immigration operations in the state.
Alex Pretti, the man shot and killed by a Border Patrol agent, was born in Illinois, the Associated Press reported.
The Department of Homeland Security says he was armed with a gun while Minneapolis Police say he had the legal right to carry one.
The Department of Homeland Security alleged the man "approached U.S. Border Patrol officers with a 9 mm semi-automatic handgun."
The 37-year-old American citizen killed by a Border Patrol agent was identified as Alex Pretti, according to the AFGE Professional Local 3669, which represents professional employees affiliated with the Minneapolis VA Health Care System.
"[A] member of our union lost their life today, and that alone is devastating. Our hearts are heavy, and we are deeply stricken by this tragedy that has befallen one of our own," the union said.
The American Nurses Association also released a statement saying it is "deeply disturbed" by the Pretti's death.
The ANA is calling for a "a full, unencumbered investigation" and urged findings to be shared with Pretti's family and the public.
The Associated Press reported that Pretti worked as an ICU nurse and was born in Illinois.
Minnesota Governor Tim Walz lashed out against President Donald Trump, Border Patrol Commander Greg Bovino and other administration officials over the shooting and reiterated his call for federal agents to leave the state.
The fatal shooting is also drawing reaction in the Chicago area.
Protesters gathered in Logan Square on Chicago's Northwest Side despite frigid temperatures.
Chicago Mayor Brandon Johnson is calling to abolish ICE, while Illinois Governor JB Pritzker is calling for a stop of funding for the agency.
Governor Pritzker posted the following statement to social media:
"Masked federal agents in Minnesota just shot and killed another person. We must put a stop to Trump's ICE. Now. Stop the funding, stop the occupations, stop the killings. I am asking my fellow Republican and Democratic Governors across the nation to have a unified response. We must all stand against the lawlessness being inflicted in our states."
Mayor Johnson posted the following statement to social media:
"One day after hundreds of thousands of people took to the streets to remind us of our shared humanity, ICE murdered another innocent person in Minneapolis. We pray for the victim and their loved ones. When they come for one of us, they come for all of us. ICE must be abolished.
"We cannot allow Trump's militarized and masked police to continue killing innocent people with impunity. Chicago stands in solidarity with the people of Minneapolis who are facing this tyranny. We need ICE and CBP to get out of our cities right now."
Illinois U.S. Senator Dick Durbin posted the following statements to social media:
"Another tragic, fatal shooting by a federal immigration officer in Minnesota. This is heartbreaking and infuriating. My office is gathering information as we speak. But what we do know: ICE's egregious, reckless behavior in our communities must come to an end. Now."
"I will not vote to fund the illegal DHS and ICE operations that terrorize Chicago, Minneapolis, and many other communities. The deaths of innocent Americans and the detaining of thousands of innocent people are a national disgrace. Secretary Noem refuses to appear before the Senate Judiciary Committee to account for her stewardship over this reign of terror. I will not reward her arrogance and lawlessness with my vote."
Illinois U.S. Senator Tammy Duckworth posted the following statements to social media:
"ICE just violently swarmed, shot and killed another person in Minnesota. They shot him again and again, long after he stopped moving on the ground. ICE cannot be trusted. We need oversight. We need accountability. And. No. More. Funding."
"Public executions at the hands of the government should never happen in 'the land of the free.' Not one more taxpayer dollar for Trump's DHS, CBP or ICE."
READ MORE | What we know about Alex Pretti, ICU nurse killed by federal agent in Minneapolis shooting
Cellphone video captured the apparent tussle between federal agents and a man on the ground in Minneapolis Saturday morning, before gunfire could be heard.
President Trump, posting on social media a picture of what he says was the man's loaded gun, saying "LET OUR ICE PATRIOTS DO THEIR JOB!"
Border Patrol Commander Bovino spoke Saturday about what led up to the shooting while agents were trying to arrest an undocumented man.
"During this operation, an individual approached U.S. Border Patrol agents with a 9 mm semiautomatic handgun," Bovino said. "The agents attempted to disarm the individual, but he violently resisted."
Police said the man shot and killed was a 37-year-old U.S. citizen and Minneapolis resident, and a lawful gun owner with a permit to carry.
This is now the third shooting in Minnesota during the ongoing immigration operation in the state. Demonstrations have already been going on after the fatal shooting of Renee Good earlier this month.
A chorus of demonstrators Saturday at a vigil in Minnesota cried out against the ongoing immigration operations.
"The chaos that we are seeing is caused directly by ICE, Border Patrol, and this federal administration," Minneapolis Mayor Jacob Frey said.
The Department of Homeland Security, posting to social media a picture of the semiautomatic handgun, the agency says, Pretti was armed with when he approached agents while they trying to arrest an undocumented man.
"This individual showed up to impede a law enforcement operation and assaulted our officers," Department of Homeland Security Sec. Kristi Noem said. "They responded according to their training."
Minnesota's gun laws permit open carry if the gun owner has a valid permit, which Minneapolis police say Pretti did.
ABC News obtained a new court filing, in which an unnamed witness, disagreeing with DHS' account, says Pretti was only trying to help another woman up from the ground. The witness said "I didn't see him touch any of them. He wasn't even turned toward them."
ABC7 Chicago Police Affairs Consultant Bill Kushner weighed in Saturday night.
"He has no right to draw a weapon at a federal agent, at any law enforcement officer. I did not see a weapon drawn," Kushner said. "What we're going to need to wait and see, before there's a rush to judgment, is body camera footage; unedited, unredacted."
ABC News has also learned Pretti had no criminal history and was a registered nurse with the VA in Minneapolis.
The Associated Press, confirming Pretti was born in Illinois and grew up in Green Bay, Wisconsin.
Pretti's father told the AP his son was an avid outdoorsman who protested immigration operations before, and referenced a conversation he had two weeks ago, saying he told his son, "go ahead and protest, but do not engage... And he said he knows that. He knew that."
Minnesota Governor Tim Walz is now calling for the shooting to be investigated by the state.
"Minnesota's justice system will have the last word on this. It must have the last word," Walz said. "The federal government can not be trusted to lead this investigation."
The Minnesota National Guard was activated in the state to assist local law enforcement maintain safety. The deployment is a request from local officials with no federal involvement.
Illinois Representative Brad Schneider is calling for a full investigation into the shooting and the firing of Homeland Security Secretary Kristi Noem.
"Trust is lost, and it's why Trump's ICE has to go," Pritzker said. "We have to figure out what we're going to do to replace it with something responsible and with responsible people."
ABC News and the Associated Press contributed to this report.