"The Fed took no action at this meeting but strongly hinted that there will be further easing action at the next meeting in September," said David Jones, chief economist at DMJ Advisors.
The statement was approved on an 11-1 vote. Jeffrey Lacker, president of the Federal Reserve Bank of Richmond, dissented for a fifth time this year. He objected to the Fed including language in the statement about keeping short-term rates low until late 2014.
U.S. economic growth slowed to an annual rate of just 1.5 percent from April through June, down from a 2 percent rate in the first quarter.
Fed officials have signaled in speeches their concern about job growth and consumer spending. Bernanke told Congress two weeks ago that the Fed is prepared to take further action if unemployment stays high.
Worries have also intensified the U.S. economy will fall off a "fiscal cliff" at the end of the year. That's when tax increases and deep spending cuts will take effect unless Congress reaches a budget deal. A recession could follow, Bernanke has warned.
Economists also worry that the debt crisis in Europe could intensify. Borrowing costs are too high for many governments, including Spain and Italy, and growth is slowing across the region as the effects of budget-cutting take hold.
Unemployment hit a record 11.2 percent in June for the 17 countries that use the euro currency.