"Bouts of sharp volatility and risk aversion in markets have recently re-emerged in reaction to concerns about both European sovereign debts and developments related to the U.S. fiscal situation, including the recent downgrade of the U.S. long-term credit rating by one of the major rating agencies and the controversy concerning the raising of the U.S. federal debt ceiling," Bernanke said.
"It is difficult to judge by how much these developments have affected economic activity thus far, but there seems little doubt that they have hurt household and business confidence and that they pose ongoing risks to growth," he added.