The killing of a United States citizen by a federal immigration agent on Saturday, the second in Minneapolis this month, sparked fresh protests and impassioned demands by local leaders for the White House to end its operation in the city, a move experts say will likely further fuel disputes and divisions in the US.

The US Department of Homeland Security characterized the incident as an attack, saying a Border Patrol agent fired in self-defense after a man approached with a handgun and violently resisted attempts to disarm him.

The DHS pointed to a pistol and ammunition it said was discovered on the man, identified as 37-year-old Alex Pretti. "He was there to perpetuate violence," Secretary Kristi Noem told a briefing, while White House deputy chief of staff Stephen Miller referred to Pretti as an "assassin".

However, bystander videos from the scene verified and reviewed by Reuters showed Pretti holding a phone in his hand, not a gun, as he tried to help other protesters pushed to the ground by immigration agents.

Demonstrations broke out across the country on Saturday. Protesters in Minneapolis dragged garbage dumpsters from alleyways to block the streets, and people who gathered chanted, "ICE out now" and "Observing ICE is not a crime", referring to the US Immigration and Customs Enforcement.

The shooting also raised tensions between state and federal officials, already at odds with the US administration over the shooting of another US citizen, Renee Good, on Jan 7.

The administration quickly claimed, as it did after Good's death, that Pretti had intended to harm the federal agents, even as video of the incident appeared to contradict their account.

As with Good's death, cellphone footage of the incident also raised serious questions about the federal government's description of the incident.

Minnesota Governor Tim Walz called the shooting "horrific" and demanded state authorities lead the investigation on Saturday. "The federal government cannot be trusted to lead this investigation. The state will handle it," he told a news conference.

Detention deaths

At least six immigrants have died in federal detention this month, marking an unusually rapid rise in deaths as the current US administration sharply intensifies immigration enforcement.

Backed by a record $170 billion in funding for immigration agencies through September 2029, the crackdown has recently focused on Minneapolis, where about 3,000 federal agents have been deployed.

This recent incident has further escalated regional tensions, widened the rift between federal and local authorities, and laid bare deep-seated contradictions within the US, experts said.

Chen Hong, director of the Asia Pacific Studies Center at East China Normal University in Shanghai, said that the US federal government's high-intensity crackdown on undocumented immigrants is likely to create a chilling effect, severely undermining social cohesion and eroding mutual trust among different ethnic groups within the US.

Deaths during law enforcement operations have triggered widespread protests and escalated into a nationwide controversy, further deepening divisions across the country, Chen said. He believes that sharply opposing narratives about law enforcement from different camps are likely to harden positions and intensify social tensions.

The standoff between the federal and state governments may spill over into Congress, he added.

"On Capitol Hill, issues such as immigration policy, homeland security funding, law enforcement authorizations and oversight hearings are likely to become flashpoints of intense partisan confrontation. This could escalate into a budgetary dispute, thereby heightening the risk of a federal government shutdown."

Li Haidong, a professor at China Foreign Affairs University, said that Minnesota, as a state long governed by Democrats, is known for its diverse and inclusive immigrant culture. However, the Republican-led federal government's recent immigration crackdown is widely seen as an attempt to reshape the local voter base through mass deportations of undocumented immigrants and even some legal residents.

These policies have severely disrupted Minnesota's long-established cultural ecosystem and social fabric, triggering widespread public discontent and deepening societal tensions, Li said.

As the midterm elections draw closer, immigration is set to become the main battleground in partisan politics, with both sides locked in fierce confrontation over policy direction. Chen said that as a result, US politics will likely slide further into turbulence and dysfunction this year.

Agencies contributed to this story.