U.S. stocks are falling at the opening of trading. Uncertainty about a deal between Greece and its creditors to ease its debt burden is weighing on investor sentiment.
Minutes after the opening bell, the Dow Jones industrial average is down 105 points, or 0.8 percent, to 12,554.
The broader S&P 500 index is down 12 points, or 0.9 percent, to 1,303. The Nasdaq composite is down 26 points, or 1 percent, to 2.789.
European leaders gathering in Brussels hope to focus on how to stimulate economic growth when huge government spending cuts threaten to push many countries back into recession.
The latest data showed Spain's economy shrank in the last three months of 2011.
European markets are also falling. France's CAC 40 and Germany's DAX lost 1.3 percent.