Pennsylvania Gov. Josh Shapiro said Sunday that tech mogul Elon Musk’s plan to give money to registered voters in Pennsylvania is “deeply concerning” and “it’s something that law enforcement could take a look at.”

Shapiro’s comments on NBC News’ “Meet the Press” come one day after Muskannounced in Pennsylvania that every day until Election Day, he would give $1 million to a random registered voter who signs a petition circulated by his super PAC “in favor of free speech and the right to bear arms.”

The super PAC has made signing the petition a prerequisite for attending rallies headlined by Musk, and on Saturday he surprised one rally attendee by giving away the first $1 million check onstage.

Shapiro, a Democrat, made clear on Sunday that his political differences with Musk, who has endorsed former President Donald Trump and pledged to use millions of dollars to turn out Pennsylvania voters for the former president via his super PAC, are not driving his skepticism of these cash prizes.

“Musk obviously has a right to be able to express his views. He’s made it very, very clear that he supports Donald Trump. I don’t. Obviously we have a difference of opinion,” Shapiro said, adding: “I don’t deny him that, right, but when you start flowing this kind of money into politics, I think it raises serious questions.”

Questions about the legality of these cash payments abounded on Saturday night, as election law experts pointed to various provisions in federal law that prohibited making cash payments to voters.

Rick Hasen, a law professor at the University of California, Los Angeles, director of the Safeguarding Democracy Project and an NBC News election law analyst, called the payments “clearly illegal” in a post on his website Saturday night.

He pointed to a federal law, 52 U.S.C. 10307(c), which says that any individual who “pays or offers to pay or accepts payment either for registration to vote or for voting shall be fined not more than $10,000 or imprisoned not more than five years, or both.”

Hasen told NBC News on Sunday that Musk’s PAC is only offering the payments to registered voters, not the general public at large, which is what could make the scheme illegal.

“Essentially what you’re doing is you are creating a lottery. You’re creating a lottery where the only people eligible to participate in the lottery are people who register to vote, or are registered to vote, and that’s illegal,” Hasen said.

He noted that the general intent behind election laws prohibiting bribery is to prevent people from buying votes, but “you don’t have to say you have to vote for a particular candidate in order to be breaking this law. ... It can be to either incentivize people to register or vote, or it can be to reward them,” Hasen told NBC News on Sunday.

Musk and a representative for America PAC did not immediately respond to requests for comment on this story.

It’s unclear whether federal authorities are looking into Musk’s $1 million payments, but Hasen said that federal authorities have the option to prosecute Musk or simply issue a warning telling the mogul to stop paying registered voters in this way.

“It seems like if this law is going to be enforced, it needs to be deterred,” Hasen said.