Prosecutors in Philadelphia have sued to stop Elon Musk and his political throng America PAC from awarding $1m (£770,092m) to voters in swing states, accusing the billionaire of “running an illegal lottery”.

“America PAC and Musk must be stopped, immediately, before the upcoming Presidential Election on November 5, ” Philadelphia District Attorney Lawrence Krasner said in the lawsuit.

The lawsuit comes days after the US fairness department warned Musk’s PAC that its $1 million giveaway might violate federal election law.

Musk, who has been aggressively campaigning for Donald Trump, has said voters who desire to be eligible for the prizes do not require to register as Republicans or vote.

As part of that attempt, Musk announced in October that he would randomly award a $1m prize to people in battleground states – Pennsylvania, Georgia, Nevada, Arizona, Wisconsin, Michigan and North Carolina – every day until 5 November.

To be eligible to triumph, the giveaway requires registered voters to release personal identifying information, like addresses and phone numbers. They are also required to sign a pledge that says they back the US Constitution.

So far, nine $1m-prize winners have been announced, the latest a man from Michigan.

Vice President Kamala Harris and Trump, whom Musk supports, remain locked in tight races in the battleground states.

Musk’s shift has been met with swift backlash from Democrats who are accusing him of attempting to buy votes, and has also drawn legal scrutiny.

“America PAC and Musk are lulling Philadelphia citizens… to provide up their personal identifying information and make a political pledge in swap for the chance to triumph $1 million,” according to the district attorney’s lawsuit filed on Monday. “That is a lottery. And it is indisputably an unlawful lottery.”

The lawsuit also accuses Musk of violating buyer protection laws by deploying “deceptive, vague or misleading statements” that could make confusion.

District Attorney Krasner has asked for an immediate injunction before the presidential election because, he says, the “scheme” was hatched to “influence voters”.

A court hearing on Mr Krasner’s request for a preliminary injunction has been set for Friday morning in Philadelphia – three days before election day.

The lawsuit makes obvious that it is not accusing Musk and America PAC of violating federal laws prohibiting vote buying.

A representative for America PAC told ABC information after the lawsuit was filed that it was fair to “infer” the PAC plans to continue handing out the $1m cheques.

The BBC has reached out to Musk’s America PAC for comment.

Legal experts told the BBC that whether the giveaway violates federal law is a bit of a grey area.

Last week, the fairness Department sent a note to America PAC warning that his lottery-style giveaway may be illegal.

It was sent by the DOJ’s community Integrity Section following outrage from Democrats over the liquid assets stunt.

Under US law, it is illegal to pay people to register to vote. But it remains ambiguous whether the sweepstakes breaks any laws.