U.S. economic growth in the first quarter of 2010 had been revised down to an annual rate of 3 percent from the 3.2 percent previously reported, the Commerce Department said Thursday.

The gain was also slightly weaker than the 3.4 percent increase that analysts had expected.

The U.S. government usually releases three estimates of the quarterly gross domestic product (GDP) -- the value of all goods and services produced within the United States.

The department said the increase in real GDP in the first quarter primarily reflected positive contributions from personal consumption expenditures.

Consumer spending rebounded at a 3.5 percent pace in the first quarter, the strongest showing since early 2007 -- before the economy tipped into a recession.

The increase in consumer spending, though down from the initial estimate of 3.6 percent, marked a big improvement from the fourth quarter, when it grew 1.6 percent.

In the first three months of this year, the increase in business investment, meanwhile, was revised down to 13.1 percent from the initial estimate of 14 percent.

Many economists believe U.S. economic growth may slow in the second half of the year as government stimulus policies wane.

According to the latest World Economic Outlook report released by the International Monetary Fund last week, the U.S. economy was expected to grow 3.1 percent in 2010, but only 2.6 percent in 2011.

But the Federal Reserve last week revised up its forecast of the U.S. economic growth this year, with lower unemployment.

According to the U.S. central bank, the economy could grow between 3.2 percent and 3.7 percent this year. That is stronger than its forecast of a growth range of 2.8 percent to 3.5 percent in January.

The unemployment rate would fall to between 9.1 and 9.5 percent by the end of the year, down from the previous estimates of 9.5 to 9.7 percent.