U.S. stocks dropped amid concerns over the COVID-19 pandemic on Monday, despite the Federal Reserve announcing it would buy as many Treasury bonds and mortgage-backed securities as necessary to keep the financial system afloat.

The Dow Jones Industrial Average ended the day at 18-thousand-592, down 582 points, or three percent.

The S&P 500 fell nearly 68 points, or two-point-nine percent, to close at two-thousand-237, while the Nasdaq slipped close to 19 points, or point-three percent, to finish at six-thousand-861.

The central bank, which had cut its key interest rate to nearly zero, said it also expects to announce a "Main Street Business Lending Program" to support eligible small and medium-sized businesses.

But the Trump administration's stimulus bill worth more than one trillion dollars was stalled in the Senate, as Democrats objected to some parts of it.

Over in Europe, the FTSE 100 closed at four-thousand-994, dropping three-point-eight percent, and the DAX index ended at eight-thousand-741, after losing two-point-one percent. The CAC 40 finished at three-thousand-914-point-31 points, shedding three-point-three percent.