The program that will be extended, "Operation Twist," was initiated by the Fed last year to keep long-term borrowing rates low on loans such as mortgages through a shift in the Fed's portfolio toward securities with maturities of six years or longer.

The Fed will continue for the rest of 2012 to sell short-term securities and buy long-term securities, shifting the balance of the central bank's portfolio.

"This continuation of the maturity extension program should put downward pressure on longer-term interest rates and help to make broader financial conditions more accommodative," the Fed said in a statement accompanying its decision.

Bernanke reiterated during the press conference that interest rates would remain at their historically low range of 0% to 0.25% until at least late 2014.

Pressure Rising on Fed

Pressure has been rising on the Fed to get off the sidelines and provide new stimulus as one piece of data after another has revealed weakness in the U.S. economy.