U.S. Federal Reserve Chairman Ben Bernanke Monday robustly defended the bank's unconventional program to stimulate the U.S. economy, quantitative easing.

Bernanke, the head of the world's most powerful central bank, said, in a Monday speech to the Economic Club of Indiana, that although the nation's weak economic performance and high unemployment had compelled the Fed to use unconventional tools that have lowered interest rates effectively to zero, the Fed's twin goals of price stability and maximum employment have not changed.

"These goals mean, basically, that we would like to see as many Americans as possible who want jobs to have jobs, and that we aim to keep the rate of increase in consumer prices low and stable," Bernanke told the Economic Club of Indiana.