Bernanke defends bond-purchase plan, warns China

WASHINGTON (AP) — Federal Reserve Chairman Ben Bernanke hit back at critics, both at home and abroad, who have challenged the central bank's $600 billion bond-purchase program.

In a speech in Germany, he argued that Congress must help support the Fed's program with further stimulus aid. And he issued a stern warning to China, saying it and other emerging nations are putting the global economy at risk by keeping their currencies artificially low.

Bernanke made the remarks today at a banking conference in Frankfurt.

Without more stimulus, high unemployment could persist for years, he said. But in making that argument, Bernanke risks heightening complaints that he's plunging the Fed into partisan politics.

The Fed's Treasury bond-buying program is intended to invigorate the economy in part by lowering interest rates, lifting stock prices and encouraging more spending. Lower interest rates on loans would prompt companies to borrow and expand.