Washington DC - President Donald Trump torched any notions of a more conciliatory approach to Minneapolis by unleashing a personal attack on Alex Pretti, who was killed by immigration officials last week.

"Alex Pretti's stock has gone way down with the just released video of him screaming and spitting in the face of a very calm and under control ICE Officer," Trump wrote, referring to footage that has emerged of the 37-year-old ICU nurse clashing with federal agents 11 days before his death.

The Republican also called Pretti an "agitator" and "perhaps, insurrectionist."

The White House has scrambled to stem widespread outrage over the killing, which came weeks after Renee Good, another US citizen and a mother-of-three, was fatally shot by an ICE in Minneapolis.

Trump had said he wanted to "de-escalate a little bit," and appointed a new point man in Minneapolis, so-called "border czar" Tom Homan, who said on Thursday that some federal agents could be withdrawn from the city after weeks of protests against immigration raids.

Backlash over the deaths of Pretti and Good, and the mass deployment of ICE agents in Minneapolis, has landed in Congress, with the Senate edging closer to a vote on Friday on a funding deal to avert a government shutdown over the crisis.

Democrats have drawn a red line around funding for Homeland Security, demanding it be stripped out and renegotiated to impose new constraints on immigration enforcement agencies.

However, Trump has still not let up on his hateful rhetoric.

After Minnesota Congresswoman Ilhan Omar was attacked during a townhall event this week, he baselessly suggested the incident had been staged.