Tech billionaire Elon Musk has said he will give away $1 million a day to a registered voter in key swing states until the US presidential election on November 5.

The winner will be chosen at random from those who sign a pro-US Constitution petition from Musk’s campaign group AmericaPAC, which he founded to support Republican candidate Donald Trump’s bid to return to the White House.

The first lottery-style check was given away to a surprised attendee at a town hall event in Pennsylvania on Saturday evening. Another check was handed out on Sunday.

Pennsylvania Governor Josh Shapiro, a Democrat who is backing Kamala Harris, called Musk’s strategy “very concerning.”

Shapiro told NBC News’ Meet the Press that law enforcement officials may have to look into the payments.

The contest is open to voters in Pennsylvania, Georgia, Nevada, Arizona, Michigan, Wisconsin and North Carolina. all major theaters of war that will ultimately decide the elections for the White House.

Election law expert Rick Hasen wrote about this personal blog about voting rights that he believed Musk’s offer was “clearly illegal.”

Federal law states that anyone who “pays or offers to pay or accepts any payment for registration to vote or to vote” faces a possible $10,000 fine or five years in prison.

Although Musk is technically asking voters to sign a form, Hasen questioned the intent behind the strategy.

“Who can sign the petitions? Only registered voters in swing states, which makes it illegal,” said Hasen, a professor at the University of California, Los Angeles (UCLA) law school.

Those who sign the petition — which pledges to support free speech and gun rights — must provide their contact information, which may allow AmericaPAC to contact them about their vote.

Both Mr Musk and AmericaPAC have been contacted for comment.

Campaigns and political action committees rely on tactics such as signing petitions, survey requests or purchasing merchandise to build massive databases of voter information. That data can then be used more precisely to target voters, or raise money from supporters who are already on board.

In Pennsylvania, Musk is giving voters $100 for signing the petition, plus another $100 for each person they refer who signs. Voters in other battleground states will get $47 per referral.

But the strategy could be covered by a loophole in US election law, as no one is paid directly to vote – despite introducing money into a process that could identify likely Trump voters.

In the US, it is illegal to provide payments to get people to vote – not just for a particular candidate, but also to simply vote.

The rule prompted ice cream maker Ben & Jerry’s to give its product free to everyone on Election Day in 2008, after initially planning to limit it only to those with an “I Voted” sticker.

During his campaign on Sunday, Trump was asked about Musk’s giveaway.

“I haven’t followed that,” he said, adding that he speaks with Musk often and that he is a “friend.”

The founder of SpaceX and Tesla and owner of X, formerly Twitter, has emerged as a major Trump supporter.

Musk launched AmericaPAC in July with the aim of supporting the former president’s campaign.

He has so far donated $75 million to the group, which has quickly become a central player in Trump’s election bid.

The Trump campaign relies heavily on outside groups like AmericaPAC to recruit voters.

A statement on the group’s website reads: “AmericaPAC was founded to support these key values: secure borders, safe cities, sensible spending, due process, free speech, right to self-protection.”

Musk said he wants to “get more than a million, maybe two million voters in the battleground states to sign the petition in support of the First and Second Amendments.”

“I think it sends a crucial message to our elected politicians,” he added.

According to the American business magazine Forbes, Musk is currently the richest man in the world, with an estimated fortune of $248 billion.