WASHINGTON: US President Joe Biden has urged Americans to stand guard against a `dangerous` oligarchy forming under Donald Trump as he delivered a dark farewell address before stepping down next week.

In a primetime speech on Wednesday from the Oval Office at the end of his single term in office, he warned of an ultra-wealthy `tech industrial complex` that he said could gain unchecked power over the American people.

`Today, an oligarchy is taking shape in America of extreme wealth, power and influence that literally threatens our entire democracy, our basic rights and freedoms,` the 82-year-old Democrat said.

Biden began his speech by touting the legacy of his four years in office, saying it may take time to feel the benefits but that the `seeds were planted` for Americans in the future.

He then lashed out at social media firms, with Musk having turned X into a right-wing megaphone and Meta boss Mark Zuckerberg ending fact-checking operations in the US as he courts Trump. `Americans are being buried under an avalanche of misinformation and disinformation,` said Biden.

`The free press is crumbling. Editors are disappearing. Social media is giving up on fact checking. The truth is smothered by lies told for power and for profit.

He recalled a stark warning issued by president Dwight Eisenhower in his own farewell address in 1961 about the dangers of an out-of-control military industrial complex. `I`m equally concerned about the potential rise of a tech industrial complex,` he said.

He also cautioned over the rise of AI, saying that America must take the lead over China on the transformative technology.

`It`s been the highest honour of my life to lead you as commander in chief,` said Biden. Signing off as Trump returns for a second term on Monday, Biden told Americans: `Now it`s your turn to stand guard.

In emotional scenes, First Lady Jill Biden, son Hunter and Vice President Kamala Harris were in the Oval Office as Biden delivered his political swansong.-AFP