Bernanke said that over time the government's increasing debt would inhibit the growth of the country's economy, the world's largest.

　　The U.S. economy has recovered sluggishly from its 2007 to 2009 recession, the country's worst in seven decades. Bernanke called the U.S. economic growth "frustratingly slow," and said the pace has left the economy "vulnerable to shocks."

　　U.S. employers have been adding more workers to their payrolls, but not fast enough to substantially reduce the unemployment rate. It was 8.5 percent in December and economists are predicting it will remain at that level when the government releases its January figure on Friday. Companies added 200,000 jobs in December, a figure analysts say perhaps fell to 155,000 last month. About 13 million U.S. workers are unemployed.

　　The government said the number of workers making their initial claims for unemployment benefits dropped 12,000 last week to 367,000. The weekly number has fluctuated somewhat recently, but over several months has dropped. Economists say that when it consistently falls below 375,000, it is an indication that more hiring is occurring and the jobless rate is likely to go down.