WASHINGTON — President Joe Biden used his farewell address to the nation Wednesday to deliver stark warnings of an “oligarchy” of the ultra-wealthy taking root in the country and of a “tech-industrial complex” that is infringing on Americans’ rights and the future of democracy.

Speaking from the Oval Office as he prepares to hand over power Monday to President-elect Donald Trump, Biden seized what is likely to be his final opportunity to address the country before he departs the White House to spotlight the accumulation of power and wealth in the U.S. among just a small few.

“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, and a fair shot for everyone to get ahead,” Biden said, drawing attention to “a dangerous concentration of power in the hands of a few ultra-wealthy people. Dangerous consequences if their abuse of power is left unchecked.”

Invoking President Dwight Eisenhower’s warnings about the military-industrial complex when he left office in 1961, Biden added, “I’m equally concerned about the potential rise of a tech-industrial complex that could pose real dangers to our country as well.”

Biden used his 15-minute address to offer a model for a peaceful transfer of power and — without mentioning Trump by name — raise concerns about his successor.

It marked a striking admonition by Biden, who is departing the national stage after more than 50 years in public life, as he has struggled to define his legacy against the return of Trump to the Oval Office. The president warned Americans to be on guard for their freedoms and their institutions during a turbulent era of rapid technological and economic change.

His speech in the Oval Office is the latest in a series of remarks on domestic policy and foreign relations that were intended to cement his legacy and reshape Americans’ grim views on his term. Earlier in the day, he heralded a long awaited ceasefire agreement between Israel and Hamas, which could end more than a year of bloodshed in the Middle East.

“It’ll take time to feel the full impact of what we’ve done together but the seeds are planted and they’ll grow and they’ll bloom for decades to come,” Biden said, tacitly acknowledging that many Americans say they have yet to feel the impacts of his trillions of dollars in domestic initiatives.

Biden sounded the alarm about oligarchy as some of the world’s richest individuals and titans of its technology industry have flocked to Trump’s side in recent months, particularly after his November victory. Billionaire Elon Musk spent more than $100 million on helping Trump get elected, and executives like Meta’s Mark Zuckerberg and Amazon’s Jeff Bezos have donated to Trump’s inaugural committee and made pilgrimages to Trump’s private club in Florida for audiences with the president-elect.

While Biden criticized social media companies for retreating from fact-checking on their platforms, Trump’s incoming communications director and press secretary were sharing posts on X that falsely claimed it was a prerecorded speech. The incumbent president has blamed his poor standing among the public on misinformation on social media and the challenges he has faced reaching voters in the disaggregated modern media ecosystem.