After Trump calls him 'a fool,' Portland mayor says support us or stay out of the way

A day after a deadly shooting in downtown Portland, President Donald Trump and Mayor Ted Wheeler were in a war of words after Trump called the mayor "a fool."

One person was killed Saturday night as protests in Oregon's largest city entered their fourth month.

Portland police officers found a person with a gunshot wound to the chest, after hearing gunfire in the area of Southwest 3rd Avenue and Southwest Alder Street at 8:46 p.m. local time, according to a press release from the Portland Police Department. Medics responded and pronounced the victim dead at the scene, officials said.

A homicide investigation is underway. No suspect information is being released at this time, police 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," Portland Police Chief Chuck Lovell said in a statement early Sunday. "If anyone can provide information about this case, I ask them to please reach out to our detectives. This violence is completely unacceptable and we are working diligently to find and apprehend the individual or individuals responsible."

The deadly shooting occurred as dueling demonstrations roiled downtown Portland. A car rally in support of President Trump had gathered earlier in the evening in a massive procession that was ultimately met by counterprotesters supporting the Black Lives Matter movement. Portland ABC affiliate KATU reported seeing clashes between the two groups on the streets.

Investigators have not said whether the shooting was connected to the demonstrations or clashes.

According to a separate press release from the Portland Police Department, there were "hundreds of vehicles" that participated in Saturday's rally and a "significant number" drove into downtown as part of the procession. People in the cars "periodically exchanged words" with pedestrians and, at times, fights broke out. There were also some minor collisions, police said.

"Portland Police responded to scenes of fights, disturbances and collisions throughout downtown and made some arrests," police said in a statement early Sunday.

The caravan of vehicles left the downtown area by about 8:30 p.m. local time, according to police. Over the next two hours, groups of people moved through downtown streets and there was "sporadic fighting and vandalism," police said. The crowds slowly began to dissipate around midnight.

Police arrested 10 people overnight, mostly for disorderly conduct. There were some skirmishes between rally-goers and counterprotesters, officials said.

Portland's mayor called for people on all sides to end the violence.

"It doesn't matter who you are or what your politics are. We have to all stop the violence," Wheeler said at a Sunday afternoon press briefing.

Trump took to Twitter early Sunday to comment on the latest violence in Portland, calling the city's mayor "incompetent" and "a fool." While retweeting a video that purportedly showed Trump supporters in their cars firing paintballs and pepper spray at counterprotesters on the street, the president said that the "big backlash going on in Portland cannot be unexpected."

"The people of Portland won't put up with no safety any longer," he tweeted. "Bring in the National Guard!"

In response, Wheeler called on Trump to do his part to stop the violence.

"I'm going to do the work that I need to do here in my local community with my local officials to take accountability for what's happening on our streets, and I'd appreciate that either the president support us, or stay the hell out of the way," the Democratic mayor said.

Joe Biden, the Democratic presidential nominee, issued a statement Sunday condemning the violence in Portland "unequivocally," and challenged Trump to "do the same."

"It does not matter if you find the political views of your opponents abhorrent, any loss of life is a tragedy," the former vice president said.

Biden charged that the president is "recklessly encouraging violence" and that Americans are "less safe" because of him.

"What does President Trump think will happen when he continues to insist on fanning the flames of hate and division in our society and using the politics of fear to whip up his supporters?" Biden said. "He may believe tweeting about law and order makes him strong -- but his failure to call on his supporters to stop seeking conflict shows just how weak he is."

Oregon Gov. Kate Brown, a Democrat, echoed Biden in a statement on the deadly shooting.

"For the last several years, and escalating in recent months, President Trump has encouraged division and stoked violence," Brown said, referencing deadly protests in Charlottesville and Kenosha, Wisconsin. "And now, unfortunately, it is happening in Portland, Oregon."

"Whether it's his completely incompetent response to the pandemic, where nearly 200,000 have died, or his outright encouragement of violence in our streets, it should be clear to everyone by now that no one is truly safe with Donald Trump as president," she added.

Black Lives Matter protests erupted in Portland and other cities across the United States following the May 25 death of George Floyd, an unarmed 46-year-old Black man who died in Minneapolis after a white police officer was filmed kneeling on his neck as three other officers watched. The protesters are calling for an end to police brutality and racial injustice.

Many of the recent demonstrations in Portland have ended in vandalism and violence. Hundreds of protesters have been arrested by authorities there since late May, according to The Associated Press.

In a speech at the Republican National Convention on Thursday, Trump invoked Portland as a "Democrat-run" city plagued by "rioting, looting, arson, and violence."

ABC News' Alexandra Faul, Matt Fuhrman and Beatrice Peterson contributed to this report.