Former US president Donald Trump told his supporters to ask for help if needed and appeared irritable with teleprompters that he said were not working during a scorching rally in Las Vegas.

The presumptive Republican presidential nominee’s campaign hired extra medics, loaded up on fans and water bottles and allowed supporters to carry umbrellas to an outdoor rally in the Nevada city, where temperatures exceeded 37.8 degrees.

The Clark County Fire Department said most of the medical calls were related to the heat, and six people were sent to hospital while 24 others were treated on-site.

“I don’t want anybody going on me. We need every voter. I don’t care about you. I just want your vote,” Mr Trump said, adding that he was joking.

Earlier in his speech, he said the campaign would offer help to people who were feeling tired and joked that “everybody”, including the US secret service, was worried about the safety of the crowds, and not about him.

“They never mentioned me. I’m up here sweating like a dog,” he said. “This is hard work.”

Mr Trump returned to Nevada, one of the top battleground states in the November election, for his second rally since he was found guilty in a hush-money scandal.

The unprecedented conviction of a former American president has galvanised Mr Trump’s fundraising as well as his supporters, but it remains to be seen whether it will sway swing voters.

Mr Trump is scheduled to be interviewed by New York probation officials via a video conference on Monday, a required step before his July sentencing.

Temperatures in the US south west have cooled since reaching historic highs late last week but remain above normal for this time of year and topped 38 degrees at the rally, which took place at a park with little shade next to the airport.

Well into his speech, Mr Trump said it was “not as bad” as he thought it would be, and said he was angrier with the teleprompters not working well, even when he used to mock then-president Barack Obama for relying on that device.

“I pay all this money to teleprompter people, and I’d say 20 per cent of the time, they don’t work,” he said, adding he would not pay the vendor who provided the prompters. “It’s a mess.”

Campaign organisers handed out water bottles as supporters waited in line to be screened by security officers. Inside the venue, large misting fans, pallets of water and cooling tents were placed around the perimeter.

“This is a dry heat. This ain’t nothing for Las Vegas people,” Nevada Republican party chair Michael McDonald said. “But what it symbolises for the rest of the United States – we will walk through hell” to elect Donald Trump.

Mr McDonald and five other Republicans have been accused of submitting certificates to US congress falsely declaring Mr Trump the winner of Nevada’s 2020 presidential election. Their trial has been pushed back to next year.

Mr Trump said the rioters who stormed the Capitol on January 6th, 2021, to contest the election were “victims” of a “set-up”.

“They were really, more than anything else, they are victims of what happened. All they were doing is protesting a rigged election. That’s what they were doing. And then the police say, go in, go in, go in, go in,” he said. “What a set-up that was. A horrible, horrible thing.”

The conspiracy theory that the January 6th rioters were encouraged by law enforcement is widespread on the right but has no basis in fact. Many of those who were at the Capitol on January 6th have said – proudly, publicly, repeatedly – that they did so to help the then-president.

Federal and state election officials and Mr Trump’s own attorney general have said there is no credible evidence the 2020 election was tainted. The former president’s allegations of fraud were also roundly rejected by courts, including by judges Mr Trump appointed.

Mr Trump’s Nevada rally, his third in the state this year, came on the tail end of a western swing that included several high-dollar fundraisers where he was expected to rake in millions of dollars.

Democrat Hillary Clinton won Nevada in 2016 as did US president Joe Biden in 2020, but Nevada was the only battleground state where Mr Trump did better against Mr Biden than Mrs Clinton.

In the 2022 mid-term elections, Nevada governor Steve Sisolak, a Democrat, was the only incumbent governor who did not win re-election.

Mr Trump hopes his strength among working-class voters and growing interest from Latinos will push him to victory in the state.

The former president’s campaign announced a renewed push for Hispanic voters ahead of the event with a Latino Americans for Trump Coalition. Four of the speakers who warmed up the crowd before Mr Trump took the stage were Hispanic immigrants.