Former United States President Joe Biden criticized Donald Trump's policies, particularly regarding Social Security, during a speech in Chicago on Tuesday.

The speech marked his first major public appearance since leaving office in January.

Addressing disability advocates, the 82-year-old Democrat said his Republican successor had "taken a hatchet" to Social Security.

Millions of US citizens are reliant on Social Security to cover their basic needs, but there is a fear that Trump's cost-cutting policies and the efforts by his advisor Elon Musk to shrink the government will cripple the system.

Some 73 million elderly and disabled citizens are provided annually with around $1.4 trillion (roughly €1.15 trillion) in benefits.

What did Biden say?

"In fewer than 100 days, this new administration has done so much damage and so much destruction. It's kind of breathtaking," the former president said. "They've taken a hatchet to the Social Security Administration."

Biden stressed that Social Security was "more than a government program."

"It's a sacred promise we made as a nation. We know just how much Social Security matters to people's lives."

Biden said the Trump administration was "shooting first and aiming later," adding: "They want to wreck it so they can rob it. Why do they want to rob it? In order to give tax cuts to billionaires and big corporations."

He did not address Trump by name, but rather referred to him as "this guy."

The 82-year-old also struggled at times with his speech, showing the signs of aging that led to him abandoning his campaign to return to the White House.

How was Biden's speech received?

The White House denied that Trump intendent to slash Social Security benefits, with Trump's press secretary Karoline Leavitt saying, "President Trump is absolutely certain about protecting Social Security benefits for law-abiding tax-paying American citizens and seniors who have paid into this program. He will always protect that program."

Republicans appeared to brush off the speech, with Trump posting a video on social media of one of Biden's rambling anecdotes, without comment.

The former president's speech divided members of his party, with Democratic strategist Karen Finney warning that Biden's reappearance could distract from the flak Trump is receiving over his tariffs policy, especially ahead of next year's mid-term elections.

"We are finally beginning to see cracks in the armor in terms of Trump's policies," Finney said. "You don't want to become a lightning rod that distracts from Trump. And it could make it easy for Trump to change the subject to Biden."

But others, like Democratic House leader Hakeem Jeffries, felt differently.

"This is an all hands on deck moment, which is why President Biden's voice in this moment is so important," he said ahead of the speech.

Biden dropped out of last year's presidential race after a poor performance in a presidential debate with Trump, paving the way for his Vice President Kamala Harris to run, and ultimately lose to Trump.

By the time he left the White House, Biden's presidential approval rating was among the worst since the end of World War II, hovering below 40%.

Edited by: Alex Berry