(CNBC) Stocks tumbled more than 2 percent on Thursday, with the Dow on track for the worst day of 2013, dropping over 300 points on a day when Asian and European markets also plunged.

A day after Federal Reserve Chairman Ben Bernanke hinted the central bank may scale back its asset purchases later this year, the world’s markets were in turmoil.

European shares closed deeply in the red across the board with the FTSEurofirst 300 index falling nearly 3 percent. Markets in Asia were slammed, with the Japanese Nikkei closing down nearly 2 percent. South Korea’s Kospi and the Shanghai Composite traded near 2013 lows.

Note: Read our discussion guidelines before commenting.