WASHINGTON — President Joe Biden used his farewell address to the nation Wednesday to deliver stark warnings about an “oligarchy” of the ultrawealthy taking root in the country and 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 ultrawealthy people and the dangerous consequences if their abuse of power is left unchecked.”

Invoking President Dwight Eisenhower’s warnings about a 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.

Biden offered his own set of solutions for the problems that he laid out: change the tax code to ensure billionaires “pay their fair share”; eliminate the flow of hidden sources of money into political campaigns; establish 18-year term limits for members of the Supreme Court; and ban members of Congress from trading stocks.

Federal Reserve data shows the wealthiest 0.1% of the country combined holds more than five times the wealth of the bottom 50% combined.