Billionaire Elon Musk’s political action committee (PAC), America PAC, has been cautioned by the U.S. Department of Justice (DOJ) regarding its $1 million daily giveaways to registered voters, U.S. media reported on Wednesday.

The DOJ’s warning stems from concerns that Musk’s sweepstakes, which offers $1 million to one registered voter in a swing state each day until the November 5 presidential election, may breach federal laws. Federal regulations prohibit offering payments to individuals as an incentive to register to vote.

Musk, the world’s richest man and a vocal supporter of Donald Trump, announced the contest on Saturday in Pennsylvania, a key swing state expected to influence the outcome of the presidential race between Trump and Kamala Harris.

According to reports from CNN and 24sight News, the DOJ sent a letter to Musk’s PAC indicating the potential legal violation. Although the winners of the contest are selected at random, they must be registered voters and are required to sign a petition supporting “free speech and the right to bear arms.”

Danielle Lang, a professor specializing in election law at Georgetown Law School, noted that this type of contest could face “civil or criminal enforcement” from the DOJ, as offering money on the condition of voter registration contravenes federal law.

Tesla and SpaceX CEO Musk has ramped up his political activity in recent weeks, donating $75 million to a pro-Trump PAC and attending campaign rallies in support of the former president.

The Justice Department has so far declined to comment on the matter.