Alex Pretti, an ICU nurse at a VA hospital, was shot and killed by a Border Patrol officer on Saturday morning. It marks the second fatal shooting this month of a U.S. citizen in Minneapolis at the hands of a federal agent.
The incident followed the fatal shooting of Renee Good, a 37-year-old mother, on Jan. 7.
In downtown L.A., two contrasting scenes unfolded outside the federal building. On one side, protesters shouted as officers stood guard. Their anger was aimed at the agents involved in Pretti's death.
On the other, interfaith leaders held a quieter anti-ICE demonstration and vigil, praying for lawmakers to intervene.
Speakers called out the names of Pretti, Good and Keith Porter Jr., who was killed by an off-duty ICE agent in Northridge on New Year's Eve.
"I'm very concerned. I've been concerned for a while," said Rev. Jamie Edwards-Acton of Sacred Resistance for the Episcopal Diocese of Los Angeles. "This has nothing to do now it seems like with immigration."
Protests also continued in North Hollywood, Boyle Heights and other parts of the region.
"We put this together because we know that we cannot just sit idly by while this is happening, not only to our undocumented brothers and sisters, but to the people out there that are taking to the streets to document what these corrupt acts, these barbaric and dehumanizing acts, that ICE is doing," said organizer Jordan Pena. "So we thought it was important that we were right here, right now ... we need to come together and let them know that we're not going to sit idly by while these injustices continue to happen."
Los Angeles Mayor Karen Bass released a statement addressing the protests and the rising tensions.
"We must not allow fear and force to define our cities, or for the federal government to turn them into war zones," read the statement. "Operation Metro Surge, the federal government's militarized crackdown that has claimed innocent lives and terrorized countless families, is unacceptable.
Los Angeles stands firmly with Minneapolis and St. Paul and with every city defending our citizens' civil rights and civil liberties. We will oppose every attempt to silence our communities, terrorize our neighborhoods, and undermine the Constitution's protections. We will not allow it. We will resist it."
As the night continued, remaining protesters vowed to keep pushing for accountability. "The people will hold you accountable," one called out as others cheered.
The demonstrations in the L.A. area remained peaceful, in contrast to unrest reported in Minnesota, where the Department of Homeland Security said an officer had part of a finger bitten off by a protester who has since been arrested.
What we know about Alex Pretti
Pretti worked for the Minneapolis VA Health Care System as an ICU nurse, according to AFGE Professional Local 3669, which represents professional employees affiliated with the Minneapolis VA Health Care System.
The Department of Homeland Security alleged that Pretti approached border patrol agents with a 9mm semi-automatic handgun, and "violently resisted" when agents tried to disarm him. Local officials disputed that characterization.
Border Patrol commander Greg Bovino declined to give more details about the confrontation, claiming, "This situation is evolving. The investigation is ongoing. Those facts will come to light."
Minnesota Gov. Tim Walz and Minneapolis Mayor Jacob Frey, however, questioned the claims and admonished the federal government for a rush to judgment without spending more time gathering evidence.
Multiple videos of the confrontation showed federal agents spraying Pretti with a substance and pinning him to the ground before the shooting.
Minneapolis Police Chief Brian O'Hara said that Pretti was a legal gun owner and did not have a criminal record.
Minnesota's gun laws permit open carrying a handgun as long as the gun owner has a valid permit.
ABC News contributed to this report.