A man was shot dead and another seriously injured Saturday in a police-free autonomous zone created by protesters in the US city of Seattle, where officers were prevented from accessing the victims, officials said.

The area, set up as part of the nationwide protest movement following the death of unarmed African American George Floyd at the hands of a white police officer, has been a frequent target of Donald Trump.

The US president has called it a "disaster" and said people there are anarchists from the "radical left."

For nearly two weeks, protesters and activists have occupied the western city's Capitol Hill neighborhood, establishing an area described as a "no cop" zone -- an urban experiment mostly carried out with a festival-like atmosphere.

"Officers attempted to locate a shooting victim but were met by a violent crowd that prevented officers safe access to the victims," the Seattle Police Department said in a statement.

Police, who arrived at the scene around 2:30 am, were later told that the pair had been transported to the hospital by the zone's "medics," where one of the victims, a 19-year-old, was declared dead.

The Seattle 'no cop' zone is described as an urban experiment, mostly carried out with a festival-like atmosphere
The Seattle 'no cop' zone is described as an urban experiment, mostly carried out with a festival-like atmosphere AFP / Jason Redmond

The other victim, also a male "remains in the hospital with life-threatening injuries," the police department said.

Police said the shooter or shooters remained at large and that they had no description of a potential suspect. The Seattle Times reported that the shooting was not believed to be connected to the protest.

Officers' body cam footage showed the police being confronted by the protesters who kept them from entering the area.

Seattle Mayor Jenny Durkan defended the zone Thursday after Trump threatened to intervene, while Governor Jay Inslee told the president that a "man who is totally incapable of governing should stay out of Washington state's business."

At a rally late Saturday in Oklahoma, Trump referenced the episode again telling supporters: "I have an offer out. I said anytime you want we'll come in, we'll straighten it out in one hour or less."

"Now I may be wrong but it's probably better for us to just watch that disaster," Trump said.

Officials in Seattle have denied reports that left-wing activists are behind the setting up of the autonomous zone.