New York (CNN Business) Alarmed investors drove the Dow more than 650 points lower in a shortened trading session on Monday. Markets plunged after the Trump administration sent out confusing signals about markets and the economy.

The S&P 500 fell 2.7% and the Nasdaq was off 2.2%. The Dow, which fell 2.9%, and the S&P 500 suffered their biggest Christmas Eve declines ever.

Stocks initially fell following a statement on Sunday from Treasury Secretary Steven Mnuchin that he had checked on the health of the country's largest banks.

On Monday, the market recovered by late morning, but then slid even lower after President Donald Trump tweeted: "The only problem our economy has is the Fed." Investors are concerned that Trump may fire Federal Reserve Chairman Jerome Powell.

The only problem our economy has is the Fed. They don't have a feel for the Market, they don't understand necessary Trade Wars or Strong Dollars or even Democrat Shutdowns over Borders. The Fed is like a powerful golfer who can't score because he has no touch - he can't putt! — Donald J. Trump (@realDonaldTrump) December 24, 2018

Mnuchin on Sunday released an unusual statement to say he had called the CEOs of the country's biggest banks. He said the executives assured him their banks are healthy and have "ample liquidity" to lend to consumers and businesses. "Markets continue to function properly," he said.

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