Clad in tactical gear with a helmet and hurling a tear gas canister at protesters, Border Patrol commander Gregory Bovino has become the public face of US President Donald Trump's aggressive deportation campaign.

Bovino's public profile rose further in recent days as he defended violent immigration sweeps in Minneapolis, which culminated Saturday with federal agents fatally shooting 37-year-old ICU nurse Alex Pretti, the second citizen to be killed in the heavily Democratic northern city in several weeks.

The Trump administration swiftly accused Pretti of seeking to harm immigration agents, saying he was in possession of a pistol, despite footage from the scene showing that Pretti never drew a weapon, as agents fired multiple shots after throwing him to the ground.

Bovino doubled down, saying it was the agents, not Pretti, who were the victims in the confrontation.

"The fact that they're highly trained prevented any specific shootings of law enforcement, so good job for our law enforcement in taking him down before he was able to do that," Bovino told CNN's "State of the Union" on Sunday.

He added: "It's too bad the consequences had to be paid because he injected himself into that crime scene. I can't say that enough. He made the decision to go there."

Cesar Garcia Hernandez, an immigration law professor at Ohio State University, said that with the Trump administration seeking to deport millions of undocumented migrants, Bovino is the man for the job.

"He is turning the aggressive rhetoric that we see from (Homeland Security) Secretary (Kristi) Noem, President Trump and other top officials into an operational reality," Garcia Hernandez told AFP.

'Turn and burn' 

Over the past year, Bovino, who is in his mid-fifties, has directed several high-profile immigration raids, including sweeps in Los Angeles and Chicago, using what he calls the "turn and burn" tactic of moving in to make quick arrests and leaving swiftly before protesters arrive.

Bovino was leading an immigration sweep in Minneapolis when on January 7, an agent fatally shot Renee Good, a 37-year-old mother of three, in her car, an incident that prompted mass demonstrations and national outrage.

Bovino also defended his agents taking a five-year-old boy into custody last week while seeking to arrest his father, saying: "We are experts in dealing with children."

Last week, footage emerged of Bovino throwing a canister with a chemical irritant into a group of demonstrators in Minneapolis.

"I'm gonna gas. Get back. Gas is coming," he said, before hurling the cartridge at protesters as plumes of green smoke rose into the air.

Unlike many of his agents who wear masks during raids, Bovino relishes the spotlight and controversy.

When not wearing tactical gear, he is often seen in a long, double-breasted green overcoat with wide lapels that was popular during World War I and II, which, coupled with his military-style buzz cut, has some critics making unflattering comparisons.

"Greg Bovino dressed up literally as if he went on eBay and purchased SS garb," California's Democratic Governor Gavin Newsom said last week.

Bovino shot back, saying that the coat is standard-issue Border Patrol uniform, which he has owned for over 25 years, and in turn accused Democratic officials of fueling unrest with such fierce criticism of his agency.

"They're trying to portray Border Patrol agents and ICE agents as Gestapo, Nazi and many other words," he said on CNN, adding that Pretti could have been influenced by such statements.

"Did this individual fall victim, as many others have, of this type of heated rhetoric?"

To Garcia Hernandez, Bovino's actions and demeanor convey a clear message.

"He leaves no room for confusion that the Trump administration's position is that there is no room for dissent in the United States, and that is a frightening proposition," Garcia Hernandez told AFP.