Aug. 21 (Bloomberg) -- The U.S. government’s long-term budget outlook is darker than expected, with projected deficits over the next 10 years totaling $2 trillion more than had been forecast, according to an Obama administration official.

A White House budget review set for release Aug. 25 will show cumulative deficits over the next decade amounting to $9 trillion, up from $7.1 trillion that the administration predicted in May, the official said on condition of anonymity because the figures haven’t been made public.

The administration revised the estimate after taking into account more up-to-date information about how the economy performed late last year, which affected its assumptions about the future, the official said.

The nonpartisan Congressional Budget Office has estimated deficits between 2010 and 2019 will total $9.14 trillion.

The deficit, the difference between government spending and revenue, is financed by borrowing from investors in the U.S. and other countries. The borrowed money is tacked onto the national debt.

This year’s shortfall will total $1.58 trillion, about $262 billion less than previously estimated, the administration said earlier this week. The lower deficit projection for the fiscal year ending Sept. 30 is largely attributable to the administration dropping contingency plans to provide hundreds of billions in additional aid to the financial industry, the official said.

The administration’s mid-session review next week will update its economic and budget forecasts, with revised estimates of GDP growth, unemployment and next year’s projected deficit. The official declined to discuss other details in the report. The CBO is slated to issue its own revised budget outlook the same day.

To contact the reporter on this story: Brian Faler in Washington at bfaler@bloomberg.net.

Last Updated: August 21, 2009 18:07 EDT