The United States may need a second fiscal stimulus worth $200-250 billion around the end of the year, but the worst of the economic and the financial crisis is already behind us, leading economist Nouriel Roubini of RGE Global Monitor said on Thursday.

Roubini, one of the few economists who foretold much of the current financial turmoil, said a second stimulus would be necessary to boost a deteriorating labor market.

The stimulus can not be too small, but it can not be too large, Roubini said, or financial markets will become too worried about the sustainability of the U.S. debt.

(Reporting by Walter Brandimarte; Editing by Diane Craft)