Joe Biden has warned that his presidential successor, Donald Trump, will attempt to “steal” the midterm elections, in what for him is a rare public address.

Speaking in South Carolina, where he was being honored for his lifetime achievement in politics, Biden also asserted that the US is experiencing “dark days”, in a speech made hours before the Trump administration launched attacks on Iran.

Reprising a line from the 2020 campaign that saw him defeat Trump and end his first presidency, Biden told the crowd at the Columbia Museum of Art on Friday that the “battle for the soul of this nation is one that’s never really over”. He simultaneously criticized Trump’s plan to introduce potentially prohibitive voting requirements ahead of the midterms.

“Here’s the good news,” Biden continued. “In America, the power still belongs to the people for now. And the way to show the power is vote, show up and vote. And folks, when we do that, that’s bad news for Donald Trump, and he knows it.

“That’s why he’s trying to pull out more and more barriers – put them up. He’s trying to steal the election, because he knows he can’t win your vote, so he’s going to do everything he can to prevent you from wanting to vote.”

Biden, 83, has largely stayed out of the public eye since leaving office and undergoing treatment for an aggressive form of prostate cancer. He did not address his health on Friday, when he criticized Trump for his recent State of the Union address and the immigration crackdown during which federal agents killed US citizens Renee Good and Alex Pretti in Minneapolis in January.

“He doesn’t mention Renee Good, Alex Pretti … [or] offer even a word of solace to their families,” Biden said.

Biden also noted that Trump didn’t “offer a word of support, even recognition” during his speech to the victims of sex offender and disgraced financier Jeffrey Epstein, who reportedly killed himself while in federal custody in 2019. Trump was among the many former powerful friends Epstein had.

Biden’s speech came as Trump’s approval rating is at a historic low. Earlier in February, the Associated Press-Norc Center for Public Affairs Research found that 61% of Americans disapprove of his performance, while a NPR/PBS News/Marist poll more recently found that most US adults think Trump is moving the country in the wrong direction.

Biden abandoned his 2024 re-election campaign after a disastrous debate performance in June of that year. He endorsed his vice-president, Kamala Harris, to succeed him, but Trump ultimately defeated her later in the year to return to the White House.