The head of the U.S. central bank argued for more efforts to stimulate the economy on Friday, but did not say when or how such action might be taken.

U.S. Federal Reserve Chairman Ben Bernanke said current unemployment rates are too high and economic growth is too slow.

Recent comments from Federal Reserve officials show that more members are convinced that it may be time for further action.

That might happen at the next scheduled meeting of the Fed in mid-September.

The Fed has kept interest rates at record lows for the past few years. Bernanke told an audience of economic experts at a resort in Wyoming that ultra-low interest rates have helped boost economic growth.

Officials have also bought large quantities of government bonds in an effort to cut long-term interest rates and encourage investment and growth.