NEW YORK (AP) – President Joe Biden slammed Elon Musk for hypocrisy on immigration following a published report that Tesla's CEO once worked illegally in the United States. Musk, who was born in South Africa, denies the accusation.

“It turned out that this richest man in the world was an illegal worker here. No, I'm serious. He was supposed to be at school when he arrived on a student visa. He wasn't at school. He broke the law. And he's talking about all these illegals coming our way?” Biden said during his campaign on Saturday in a union hall in Pittsburgh.

The Washington Post reported that Musk was working in the country illegally while on a student visa. Citing company documents, former business partners and court documents, the newspaper said Musk came to Palo Alto, California, in 1995 for a graduate program at Stanford University, “but he never enrolled in any courses, instead working on his startup.”

In response to a video post with Biden's comments, Musk wrote on

According to the report, investors in Musk's company Zip2 were concerned about the possibility of their founder being deported and set a deadline for him to apply for a work visa. The newspaper also cited a 2005 email from Musk to his Tesla co-founders in which he admitted that he did not have residency in the United States when he started Zip2.

According to the report, that email was submitted as evidence in a now-closed defamation case in California and said Musk applied to Stanford so he could stay in the country legally.

Musk is now the richest man in the world. He has more than $70 million pledged to help Republican presidential nominee Donald Trump and other GOP candidates win on Nov. 5, and is one of the party's biggest donors this campaign season. He headlined events in the last White House campaign and often repeated Trump's dark anti-immigration rhetoric.

Trump has promised to give Musk a role in his administration if he wins next month.

There was no immediate response to messages left by X and Tesla seeking Musk's comment.