United States President Joe Biden took aim at Tesla and SpaceX CEO Elon Musk during a campaign event in Pittsburgh, Pennsylvania, on Saturday, accusing him of hypocrisy regarding immigration issues.

Biden highlighted that Musk began his career in the US as an “illegal worker” before rising to become the world’s wealthiest individual, according to a CNBC report.

Referring to Musk as a new “ally” of former President Donald Trump, Biden stated, “The wealthiest man in the world turned out to be an illegal worker here.” He noted that Musk was supposed to be attending school under a student visa but was not in compliance with the law at that time.

According to a report by the Washington Post, South African-born billionaire Musk worked illegally in the United States in the 1990s while trying to build a startup.

In response, Musk refuted such claims on Sunday, stating that he was legally allowed to work during that time. He explained on his social media platform X that he held a J-1 visa, which later transitioned to an H1-B visa. The J-1 Exchange Visitor visa permits foreign students to gain academic training in the US while the H1-B visa is intended for temporary employment.

The report noted that Musk arrived in Palo Alto, California, in 1995 to attend Stanford University but never actually enrolled in the graduate programme. Instead, he focused on developing his software company, Zip2, which was sold in 1999 for approximately $300 million.

The Washington Post cited two former Musk colleagues who recalled Musk receiving his US work authorisation in or around 1997.

President Joe Biden criticised former president Donald Trump and the Republican Party for their inability to pass legislation addressing immigration issues, particularly related to border security. He pointed out that illegal border crossings are currently at their lowest levels since Trump’s third year in office.

Meanwhile, Elon Musk recently held a series of “town hall” events in Pennsylvania, aiming to persuade voters to support Trump and his policies. During these events, Musk attracted attention by offering $1 million in lottery-style prizes to registered voters in swing states who signed a petition from his pro-Trump organization, America PAC.