The Federal Reserve said it will expand its holdings of long-term securities with open-ended purchases of $40 billion of mortgage debt a month in a bid to boost growth and reduce unemployment.

“If the outlook for the labor market does not improve substantially, the committee will continue its purchases of agency mortgage-backed securities, undertake additional asset purchases and employ its other policy tools as appropriate,” the Federal Open Market Committee said today in a statement at the end of a two-day meeting in Washington.

The FOMC said it would likely hold the federal funds rate near zero “at least through mid-2015.” Since January, the Fed had said the rate was likely to stay low at least through late 2014. The Fed said “a highly accommodative stance of monetary policy will remain appropriate for a considerable time after the economic recovery strengthens.”