The Commerce Department said the April-to-June increase in the gross domestic product - the country's total output of goods and services - was revised upward by 0.5 percentage point from its estimate just a month ago that the economy expanded at a 2.8 percent pace in the second quarter.

Even with the revision, the 3.3 percent GDP growth rate was down significantly from the 4.5 percent rate of increase turned in during the January-March quarter as consumers, buffeted by rising energy prices, cut back sharply on their spending in other areas during the spring. It marked the slowest growth rate since a 1.9 percent increase in the first three months of 2003.

Treasury Secretary John Snow called the upward revision to the second quarter GDP ''good news for the U.S. economy and American families. . . . The revision underscores the fact that the fundamentals of the economy are solid and we are in a period of rising prosperity and strong growth.''

The biggest factor contri- buting to the upward revision in second-quarter GDP growth came from a reduction in the amount of imports coming into the country from the previous estimate. Imports of foreign products subtract from growth.

Other factors contributing to the 0.5 percentage point increase in GDP was an upward revision in the estimates of U.S. exports and a larger buildup of inventories than previously believed.