Share prices on Wall Street have tumbled amid concerns about the health of European banks and fears of another global slowdown.
The Dow Jones industrial average fell closed down 268 points (2.6%) to 9,870.46 in final trades, falling below the psychologically sensitive 10,000 level.
The Nasdaq shed 85 points (3.8%) to 2,135.18 and the broad-market S&P 500 index dropped 33 points (3.1%) to a provisional close of 1,041.29.
Leading European share indices also slumped about 3% ahead of a deadline this week for banks to repay loans taken out a year ago at low interest rates, the BBC reports.
The concerns also pushed the pound to a new 19-month high against the euro.
The European Central Bank will offer funds on Wednesday to banks looking to repay 442 billion euros worth of loans later this week.