U.S. and European stock markets dropped sharply Monday on fears of a Greek debt default.

U.S. stocks traded lower at midday. Both the Dow Jones Industrial Average of 30 key stocks and the broader S&P 500 are off 1.8 percent. The technology-laden NASDAQ is down 1.2 percent.

European stocks ended even lower.

London's Financial Times 100 index fell 2 percent to end at 5,260. The CAC-40 in Paris slid 3 percent to finish at 2,940. The DAX in Frankfurt closed down 2.8 percent at 5,416.

In Asia, Japanese markets were closed Monday for a national holiday .

Hong Kong's Hang Seng index fell 2.8 percent , to end at 18,918.

Gold is trading down $30.80 at $1,780.57 an ounce.

The U.S. dollar was lower against the yen, but up against the euro.