UPDATE 1-US economy to contract in 1st half, grow in Q3-EIA

(Adds quotes, quarterly real gross domestic product)

WASHINGTON, March 11 (Reuters) - The U.S. economy will contract during the first half of the year and then rebound in the third quarter, the federal Energy Information Administration said on Tuesday.

"U.S. real gross domestic product is expected to decline slightly in the first half of the year and then start growing again, with growth for 2008 as a whole at 1.3 percent, the slowest annual rate since 2001," the EIA said in a monthly energy forecast.

It was the first official government forecast that pointed to a recession.

The EIA's forecast came days after key Bush Administration officials had maintained the economy was still poised to grow, albeit slowly.

The EIA said it expected U.S. real gross domestic product to contract from $11.577 trillion in the fourth quarter of 2007 to $11.563 trillion in the first quarter of 2008, then decline to $11.542 trillion in the second quarter, before rising to $11.633 trillion in the third quarter.

While the EIA did not specifically say the United States would slide into a recession during the first of half, two consecutive quarters of a contracting economy is a common definition of a recession. (Reporting by Tom Doggett; Editing by Walter Bagley)