One person was shot and killed late Saturday in Portland, Oregon, as a large caravan of United States President Donald Trump supporters and Black Lives Matter protesters clashed in the streets, police said.

It wasn’t clear if the shooting was linked to fights that broke out as a caravan of about 600 vehicles was confronted by counter-demonstrators in the American city’s downtown.

Police said the caravan had left the area around 8:30pm, and officers heard gunshots at about 8:46pm, according to a statement. Officers arrived at the shooting scene “within a minute”, police said, but the man who was shot did not survive.

The caravan had gathered earlier in the day at a suburban mall and drove as a group to the heart of Portland. As they arrived in the city, protesters attempted to stop them by standing in the street and blocking bridges.

Videos from the scene showed sporadic fighting, as well as Trump supporters firing paintball pellets at opponents and using bear spray as counter-protesters threw things at the Trump caravan.

The Black Lives Matter demonstrations usually target police buildings and federal buildings. Some protesters have called for reductions in police budgets while the city’s mayor and some in the Black community have decried the violence, saying it’s counterproductive.

Early Saturday morning, fires set outside a police union building that is a frequent site for protests prompted police to declare a riot.

An accelerant was used to ignite a mattress and other debris that was laid against the door of the Portland Police Association building, police said in a statement. At least one dumpster had also been set on fire in the street nearby.

The commotion followed a sit-in in the lobby of the Portland mayor’s condominium building Friday night.

The New York Times reported that Trump supporters and counter-protesters clashed on the streets, with people shooting paint ball guns from the beds of pickup trucks and protesters throwing objects back at them.

The pro-Trump vehicle rally began near Clackamas Town Center before reaching Portland on Saturday evening, with clashes breaking out thereafter between Trump supporters and counter-protesters, the Oregonian reported.

It added that the shooting took place after most of the caravan had left downtown.

Trump has been criticised for not showing empathy in the wake of shootings and killings of Black men by police, including George Floyd, who died in police custody in Minneapolis in May, sparking anti-racism demonstrations worldwide.

New protests erupted in Kenosha, Wisconsin, this week after police officers shot Jacob Blake, another African-American man, multiple times in front of his children. He survived.

Thousands of people took part in a march in Washington on Friday to denounce racism.