Wall Street surged on Thursday, with the blue-chip Dow back above 12,000, after European leaders agreed on a deal to tackle the region's debt crisis and U.S. third- quarter GDP growth accelerated.

Investors breathed a sigh of relief after European leaders agreed early Thursday, after ten hours of negotiations, that private creditors have to accept a 50 percent cut in the value of the Greek government debt they hold, and the bailout fund would be increased to 1 trillion euros (1.37 trillion U.S. dollars).

Although the full program can not be finalized until early Dec., investors were glad to see the 17-nation euro zone was finally taking a critical step to the right direction after several missed opportunities.

Boosted by the wide-spread optimism, all three major average indexes surged about 3 percent and entered positive territory for the year.

Adding to the momentum, data showed U.S. economy gained some much-needed strength in the third quarter. U.S. gross domestic product, the broadest measure of its economic health, grew at a 2. 5 percent annual rate in the quarter, nearly doubled compared to the previous three months. The Dow Jones industrial average gained 339.51 points, or 2.86 percent, to 12,208.55. The Standard & Poor's 500 jumped 42.59 points, or 3.43 percent, to 1,284.59. The Nasdaq Composite Index soared 87.96 points, or 3.32 percent, to 2,738.63.