Americans borrowed more money in July than any other month in more than three years. But they cut back on using their credit cards.

Consumer borrowing rose nearly $12 billion in July, the Federal Reserve said Thursday. Greater demand for school and auto loans fueled the increase. A category that measures credit card use fell in July after large increases in May and June.

Total consumer borrowing increased to a seasonally adjusted annual level of $2.45 trillion. That's barely 2 percent above the four-year low reached in September.

The increase in loans was largely because of a pickup in auto sales, said Troy Davig, senior U.S. economist at Barclays Capital. The March 11 earthquake in Japan caused a global parts shortage that left many auto dealers without popular models this spring. The supply chain disruptions have eased in recent months.

The category that measures auto loans rose in July by the most in more than six years.

Borrowing is usually a sign of confidence in the economy. Consumers tend to take on more debt when they feel wealthier. But an increase in credit card use can be a sign that people have fallen on harder times.

Federal Reserve Chairman Bernanke said Thursday that heavy debt loads was one reason consumers aren't spending more and using their credit cards. But even taking into account debt, "households seem exceptionally cautious," Bernanke said in a speech in Minneapolis to the Economic Club of Minnesota.

Americans have been struggling this year with high unemployment, scant raises and steep gas prices. Many economists are worried that the economy is at risk of slipping into another recession.

For the first six months of the year, the economy grew at an annual rate of just 0.7 percent. That's the slowest growth since the recession officially ended more than two years ago.

Last week, the government said the economy added no net jobs in August, and the unemployment rate stayed at 9.1 percent for a second straight month. It was the weakest month for hiring in nearly a year.

Households began borrowing less and saving more when unemployment spiked during the recession. Credit card use fell.

Economists do not expect consumers to load up on debt the way they did during the housing boom in 2006 and 2007. During that period, Americans felt wealthier and more willing to take on added debt because of the soaring value of their homes.

The Federal Reserve's borrowing report includes auto loans, student loans and credit cards. It excludes mortgages and loans tied to real estate.