Washington » Despite an optimistic assessment about the recession's end by Fed Chairman Ben Bernanke and a report showing retail sales up by the largest amount in more than three years, the byword on Tuesday was still one of caution.

Economists warned that as long as credit stays tight and jobs remain scarce, Americans probably aren't ready to spend in force again. And Bernanke advised that even though the worst recession since the 1930s is probably over, pain -- especially for the nearly 15 million unemployed Americans -- will persist.

Bernanke, cautioning that it would be many months before unemployment rates would drop significantly, added that "it's still going to feel like a very weak economy for some time, as many people will still find that their job security and their employment status is not what they wish it was."

The assessment came at the conclusion of a speech by Bernanke at the Brookings Institution marking the anniversary of the market crisis that was precipitated by the collapse of the investment bank Lehman Brothers.

Bernanke said the economy likely is growing now, but he warned that won't be sufficient to prevent the unemployment rate, now at a 26-year high of 9.7 percent, from rising. The recession, which started in December 2007, has claimed a net total of 6.9 million jobs.

With expectations for a lethargic recovery, the Fed predicts that unemployment will top 10 percent this year. The post-World War II high was 10.8 percent at the end of 1982.

Some economists say it will take at least four years for the jobless rate to drop down to a more normal range of 5 percent. Even if the economy logs "moderate" growth in 2010, unemployment is likely to stay elevated, Bernanke suggested.

"Obviously, that's a very serious concern," he said.

Drugmaker Eli Lilly & Co. said Monday that it will cut 5,500 jobs over the next two years, 14 percent of its work force, as it restructures the company into five units.

Still, Bernanke's declaration that the recession likely ended marked his most optimistic assessment yet of the economy. Analysts predict the U.S. economy is growing in the current quarter, which ends Sept. 30, at an annual rate of 3 to 4 percent. It shrank at a 1 percent pace in the second quarter, much slower than in previous quarters.

And his remarks came on the same day that the government reported that retail sales jumped 2.7 percent in August.

All that helped to lift stocks on Wall Street. The Dow Jones industrial average gained nearly 57 points to 9,683.41, its highest finish since Oct. 6.

But underscoring just how fragile the economic recovery is, Best Buy said Tuesday that customers are spending less in its electronics stores, and Kroger said grocery shoppers are still buying only what they need for the next week, or even the next meal.

The gains for August included a big jump in auto sales, mostly from the government's recently ended Cash for Clunkers program. Retail sales overall rose by a seasonally adjusted 2.7 percent, the largest gain since 2006, the Commerce Department said.

Economists were cautious. "We need more data to see if this is sustainable or just noise," Ian Shepherdson, chief U.S. economist at High Frequency Economics, wrote in a research note. "The income and credit constraints on consumers remain intense."

Auto sales were up 10.6 percent, the biggest gain in almost eight years, mainly because of the recently ended clunkers program. Gas station sales increased 5.1 percent, as prices at the pump rose.

Excluding those two categories, sales rose 0.6 percent -- still the best performance in six months.