Billionaire Elon Musk said he plans to award $1 million a day to a randomly chosen voter who has signed his petition pledging to uphold the rights to free speech and to bear arms, stepping up efforts by his America PAC political group to boost Donald Trump’s presidential prospects.

HARRISBURG, Pennsylvania, Oct 20 (Reuters) - Pennsylvania's Democratic governor, Josh Shapiro, on Sunday called on law enforcement to investigate billionaire Elon Musk for his promise at a weekend pro-Trump rally to give away $1 million each day until Election Day.

The tech billionaire kicked off the giveaways at a rally in Harrisburg on Saturday, handing a million-dollar check to a man named John Dreher.

Elon Musk was responsible for virtually all of a key pro-Trump super PAC's donations last quarter—the first concrete indicator of how much he's spending to help elect Trump.

Legal experts raised concerns about he legality of the move because it ties a monetary reward to voter registration status, which is prohibited under federal law.

Elon Musk promised to give away $1 million each day until November's election to someone who signs his online petition, with the first prize awarded at a PAC event supporting Donald Trump.

I think there are real questions with how he is spending money in this race," the governor of Pennsylvania said.

While stumping for former President Donald Trump on Saturday, tech billionaire Elon Musk announced that he will give away $1 million each day to registered voters in battleground states, immediately drawing scrutiny from election law experts who said the sweepstakes could violate laws against paying people to register.

Musk has offered swing state voters a chance to win $1 million every day until Election Day, but some question if it's legal.