A man was shot dead in downtown Portland, Oregon, on Saturday night as supporters of President Donald Trump and Black Lives Matter protesters clashed, police said.
The Portland Police Bureau said in a statement the shooting took place about 8:46 p.m. and that officers nearby heard the gunfire.
"They responded and located a victim with a gunshot wound to the chest. Medical responded and determined that the victim was deceased," the statement said.
"A Homicide Investigation is underway," it said, adding that no suspect information was being released.
Multiple videos posted to social media showed medics, police and other authorities surrounding a victim with a wound to his chest.
It was unclear if the shooting was connected to the protests.
Justin Dunlap told NBC News that he saw the victim facing two people when he heard the shots. He said he did not see the gun being fired because mace was sprayed at the same time.
The victim turned "took a few steps, then fell face down," said Dunlap, 44, adding that the two people facing him ran from the scene.
A picture from the scene published by Getty Images showed the man wearing a hat with a Patriot Prayer logo. The group is described as far-right, by the Southern Poverty Law Center.
Portland Police Chief Chuck Lovell called the violence "completely unacceptable" in a separate statement issued by the bureau early Sunday.
"We are working diligently to find and apprehend the individual or individuals responsible," he said.
"It is still early in this investigation, and I ask everyone to give the detectives time to do their important work before drawing conclusions about what took place," he added.
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Detectives were aware of videos circulating on social media that show the shooting, and are seeking "a full and accurate picture" of what happened, the statement said.
The shooting came as critics of police continue to take to the streets of Portland following the in-custody death May 25 of George Floyd in Minneapolis. On Saturday, Trump supporters joined the fray.
Video from downtown Portland near the Justice Center showed lifted four-wheel-drive trucks driving through intersections filled with protesters.
It was not immediately clear whether the differing political views had anything to do with the shooting.
Earlier in the evening, Portland police tweeted: "There have been some instances of violence between demonstrators and counterdemonstrators. Officers have intervened and in some cases made arrests."
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 counterprotesters, the Oregonian newspaper reported.
It added that the shooting took place after most of the caravan had left downtown. NBC News was not able to independently verify this.
On Tuesday, a teen suspect with an assault weapon opened fire during a Black Lives Matter protest in Kenosha, Wisconsin, leaving two people dead. The demonstration was a response to the shooting of a Black man, Jacob Blake, that was captured on cellphone video. The suspect was later identified as Kyle Rittenhouse, 17, from Illinois, who has been charged with two counts of homicide, among other allegations.
Portland has been the site of raucous protests since spring, and the Trump administration in July deployed extra federal agents to the city to protect federal property.
The mayor of Portland, Ted Wheeler, said at the time that the move only inflamed the demonstrations.