Former President Donald Trump on Tuesday made his first public appearance since Sunday's second apparent assassination attempt against him with an overflow crowd chanting “God bless Trump!” and “Fight, Fight, Fight” as US Secret Service agents surrounded the stage to protect the Republican presidential nominee.

“It's been a great experience,” Trump said in an evening town hall in Flint, Michigan, about holding events with thousands of supporters. But he also went on to call running for president “a dangerous business” akin to car racing or bull riding.

“Only consequential presidents get shot at," he said.

Earlier in the day, Vice President Kamala Harris struck a measured tone, even steering clear of mentioning Trump by name in an interview with Black journalists that starkly contrasted with the former president's own highly contentious appearance before the same group.

The two candidates briefly put their differences aside in a phone call Trump described as “very, very nice” even as crowds booed when he mentioned Harris by her first name.

“It was very, very nice, and we appreciate that,” Trump told his supporters. Harris said earlier in the day that she told Trump “there's no place for political violence in our country.”

Both sides are ramping up campaigning with no changes to Trump's calendar despite the apparent assassination attempt at one of his Florida golf courses, which has renewed accusations by Republicans that Democrats' criticism against Trump is inspiring violent attacks. Democrats have accused Trump in the past for his long history of inflammatory campaign rhetoric and advocacy for jailing or prosecuting his political enemies. But Harris was treading more carefully in the aftermath of the second apparent attempt.

The session with the National Association of Black Journalists earlier Tuesday was one of the few extensive sit-down interviews Harris has done since replacing President Joe Biden atop the Democratic ticket in July. She repeatedly criticised Trump on issues including his handling of the COVID-19 pandemic and opposition to abortion access, but was careful to refer to him as the former president and in other ways that avoided naming him directly.

Trump re-upped his past retaliation threats against election workers, donors and others as he tries to stoke fears about the integrity of the upcoming 2024 election.

He posted Tuesday on his social media site, “Those involved in unscrupulous behaviour will be sought out, caught, and prosecuted at levels, unfortunately, never seen before.”

Harris answered questions from three association journalists at a small, relatively quiet venue at the Philadelphia studios of public radio station WHYY.

That was very different from Trump's addressing the NABJ conference in Chicago in July, when he was antagonistic to the moderators and sparked an uproar by questioning the vice president's racial identity.

Her manner was a departure from her campaign rallies, where Harris often receives some of her loudest applause by declaring that her professional background as a prosecutor means, “I know Donald Trump's type.”

So far, Biden and Harris have tried to avoid politics in their responses to Sunday's incident, instead condemning political violence of all kinds. The president also urged Congress to increase funding to the Secret Service.

Trump has claimed, without evidence, that months of criticism against him by Harris and Biden, who call him a threat to American democracy, inspired the latest attack.

“I really believe that the rhetoric from the Democrats" is “making the bullets fly And it's very dangerous. Dangerous for them. It's dangerous for both sides,” Trump said in an interview with The Washington Post.

Authorities say Ryan Wesley Routh camped outside the golf course in West Palm Beach, where Trump was playing on Sunday, for nearly 12 hours with food and a rifle but fled without firing shots when a Secret Service agent spotted and shot at him.

Subsequently arrested as he drove on the highway, Routh's past online posts suggest he has not been consistent about his politics in terms of supporting Democrats or Republicans. The attack came barely two months after Trump was wounded during a rally in Pennsylvania.

Trump also met on Tuesday with sheriff's office deputies who activated the highway traffic stop that took Routh into custody.

Trump's running mate, Ohio Sen. JD Vance, said at a Georgia Faith & Freedom Coalition event on Monday that “it's popular on a lot of corners of the left to say that we have a both sides problem.” But “no one has tried to kill Kamala Harris in the last couple of months, and two people now have tried to kill Donald Trump."

White House press secretary Karine Jean-Pierre said during her briefing with reporters Tuesday that there should be zero tolerance for violence-inciting rhetoric. She bristled at the suggestion that Biden and Harris have stoked division by calling Trump a threat to democracy, saying that there were concrete examples of the former president being that — such as when he helped incite an attack on the US Capitol on January 6, 2021.

In response to Vance's comments, Jean-Pierre said, “When you have that type of language out there it's dangerous. It's dangerous because people look up to that particular national leader, and they listen to you." She said such comments open the door for "people to take you very seriously.”