Elon Musk was ordered to attend a court hearing on Thursday, days after the billionaire was sued by Philadelphia prosecutors over his $1m (£770,000) voter gifts.

The Donald Trump supporter, through his political group America PAC, offered cash prizes to registered voters in swing states who sign a petition.

US officials suggest this could violate election law – something Musk denies. Philadelphia District Attorney Lawrence Krasner said Musk “must be stopped, immediately, before the next presidential election.”

CNN reports that Musk has filed a “motion to remove” to move the matter out of state hands and into a federal judge, which could delay matters.

The court hearing in Philadelphia is scheduled to begin at 10:00 EST (14:00 GMT), according to the BBC’s US partner CBS News.

Court documents show that Philadelphia Common Pleas Court Judge Angelo Foglietta said “all parties must be present at the time of the hearing.”

Musk announced earlier this month that he would randomly award a $1 million prize to people in the battleground states — Pennsylvania, Georgia, Nevada, Arizona, Wisconsin, Michigan and North Carolina — every day until November 5.

These swing states suggest a particularly close race between Trump and his Democratic rival for president, Kamala Harris.

To be eligible to win, the giveaway requires registered voters to provide personally identifiable information such as addresses and phone numbers. They are also required to sign a pledge saying they support the US Constitution.

The lawsuit filed against Musk alleged that he “operated an illegal lottery.”

“America PAC and Musk are luring the citizens of Philadelphia … to give up their personally identifiable information and make a political commitment in exchange for a chance to win $1 million,” Mr. Krasner said in the lawsuit. “This is a lottery. And it is indisputably an illegal lottery.”

The lawsuit also accuses the Tesla co-founder of violating consumer protection laws by using “misleading, vague or misleading statements” that are likely to cause confusion.

But Musk’s lawyers argued otherwise.

“The complaint really has little to do with state nuisance and consumer protection claims,” ​​Musk’s lawyers wrote in federal filings, according to the CNN report. “Rather, although disguised in state law claims, the thrust of the complaint is to prevent by any means the defendants’ alleged ‘interference’ in future federal presidential elections.”

If the matter moves to federal court, the case would pass out of the hands of the judge in Philadelphia.

The BBC has contacted Mr Krasner for comment.

Before the case was filed, Musk’s PAC was also warned by the US Justice Department that its lottery-style gift could violate federal election law.

The BBC previously contacted America PAC for comment.

Under US law, it is illegal to pay people to register to vote. But legal experts told the BBC that whether the donation breaks federal law is a gray area.

Musk himself, who campaigned aggressively for Trump, insisted that voters who want to be eligible for the awards do not need to register as Republicans or vote.