NEW YORK — In an unprecedented move, U.S. President Donald Trump said that he’s firing Federal Reserve Governor Lisa Cook — marking a sharp escalation in his efforts to exert greater control on one of the most powerful financial institutions in the world.

Trump took to social media to announce that he would be removing Cook, effective immediately, over allegations that she committed mortgage fraud before she joined the board. In response, Cook said that she would not step down — and maintained that the president has no authority to fire her.

“President Trump purported to fire me ‘for cause’ when no cause exists under the law, and he has no authority to do so,” she said in an emailed statement. “I will not resign.”

Cook made headlines three years ago when she became the first Black woman to serve on the Fed’s board of governors, which votes on the central bank’s key interest rate decisions. Prior to her appointment to the board, she was a longtime economics professor and also held roles in the Clinton, G.W. Bush and Obama administrations.

Here’s what to know about Lisa Cook.

Cook was appointed to the Fed’s board by President Joe Biden in 2022. Her nomination was opposed by most Senate Republicans, and she was approved on a 50-50 vote with the tie broken by then-Vice President Kamala Harris.

When she took office, Cook became the first Black woman to serve as a Fed Governor in the institution’s over century-long history. She initially filled an unexpired term and was reappointed the following year. Her appointment runs through January 2038.

Cook has taught economics and international relations at Michigan State University, and was previously also on the faculty of Harvard University’s Kennedy School of Government. She was a Marshall Scholar who received degrees from Oxford University and Spelman College.

Also prior to her appointment to the Fed, she served as a senior economist on the Council of Economic Advisers under President Barack Obama from 2011 and 2012 — as well as a senior adviser on finance and development in the U.S. Department of Treasury’s Office of International Affairs from 2000 to 20021, under Presidents Bill Clinton and George W. Bush..

Fed governors vote on the central bank’s interest rate decisions — as well as other issues of financial regulation.

Board members are appointed by the president and confirmed by the Senate. But unlike cabinet secretaries — who serve at the pleasure of the president, for example — Fed governors take on 14-year terms that are staggered in an effort to insulate the Fed from political influence.

The political independence of the Fed is considered critical to its ability to fight inflation because it enables the central bank to take unpopular steps, like raising interest rates. If bond investors start to lose faith that the Fed will be able to control inflation, they will demand higher rates to own bonds — pushing up borrowing costs for mortgages, car loans and business loans.

The Trump administration has accused Cook of mortgage fraud.

Bill Pulte, a Trump appointee who heads the Federal Housing Finance Agency, made the accusations last week — alleging that Cook had claimed two primary residences, in Ann Arbor, Michigan, and Atlanta, in 2021 to get better mortgage terms. Mortgage rates are often higher on second homes or those purchased to rent.

Critics say these accusations are being used as a tool by Trump to gain control of the Fed. And Pulte has raised similar allegations against others who have clashed with the president before — including Sen. Adam Schiff, D-Calif., who led Trump’s first impeachment, and New York Attorney General Letitia James, who who sued Trump’s company over alleged fraud for falsifying records.