Elon Musk promises to award $1 million each day to a signer of his petition

Billionaire Elon Musk promised on Saturday to give away $1 million each day until November's election to someone who signs his online petition supporting the US Constitution.

And he wasted no time, awarding a $1 million cheque to an attendee of his event in Pennsylvania aimed at rallying supporters behind Republican Donald Trump. The winner was a man named John Dreher, according to event staff.

"By the way, John had no idea. So anyway, you're welcome," the Tesla founder said as he handed Dreher the cheque.

The money is the latest example of Musk using his extraordinary wealth to influence the tightly-contested presidential race between Trump and his Democratic rival Kamala Harris.

Musk started America PAC, a political action organisation he founded in support of Trump's presidential campaign. The group is helping mobilise and register voters in battleground states, but there are signs it is having trouble meeting its goals.

The Harrisburg event is the third in as many days in Pennsylvania, where Musk is painting November's election in stark terms and encouraging supporters to vote early and get others to do the same.

He said on Saturday that if Harris wins, it will be "the last election," suggesting the US will no longer exist.

He also said the two assassination attempts against Trump prove he is ruffling feathers and upending the status quo in ways Harris won't. He said that's why no one is trying to kill Harris.

"Assassinating a puppet is worthless," Musk said, reiterating an argument he has made in a social media post.

The petition Musk is asking people to sign reads: "The First and Second Amendments guarantee freedom of speech and the right to bear arms. By signing below, I am pledging my support for the First and Second Amendments."

Attendees of Saturday's event had to sign the petition, which allows America PAC to garner contact details for more potential voters that it can work to get to the polls for Trump.

Musk, ranked by Forbes as the world's richest person, so far has supplied at least $75 million to America PAC, according to federal disclosures, making the group a crucial part of Trump's bid to regain the White House.

The entrepreneur behind carmaker Tesla and rocket and satellite venture SpaceX has increasingly supported Republican causes and this year became an outspoken Trump supporter.

Trump in turn has said if elected he would appoint Musk to head a government efficiency commission.

Reuters