The head of the U.S. central bank says the Federal Reserve will take additional steps to stimulate the economy if the current lull in growth continues.

Federal Reserve Chairman Ben Bernanke spoke to a congressional committee in Washington Wednesday.

He said some of the problems that have slowed the recovery, like high oil prices, are easing and are probably only a temporary obstacle to growth.

He said economic growth will speed up in the second half of this year, and probably rise to an annual rate of around 2.8 percent.

That is faster than the first few months of this year, but slower than the last quarter of 2010.

Bernanke said the U.S. unemployment rate will fall from its current 9.2 percent, but not as quickly as previous predictions.