WASHINGTON, March 6 (Xinhua) -- As many as 7,000 more American troops may be needed for U.S. President George W. Bush's plan of sending 21,500 additional combat soldiers to Iraq, a top Pentagon official said Tuesday.

    Testifying before the House Budget Committee, Deputy Defense Secretary Gordon England said the Pentagon's estimate of support troops for the 21,500 additional combat soldiers to be deployed to Iraq could be about 4,000 and maybe as many as 7,000.

    He said Defense Secretary Robert Gates and Joint Chiefs of Staff Chairman Peter Pace had testified for the 21,500 additional troops at congressional hearings, but the number could be 10 or 15percent higher in terms of added support troops.

    "I mean, our estimate is we will be above the 21,500 by about 10 or 15 percent," he said.

    If 4,000 support troops were needed, the projected cost of the troop surge could rise by 1 billion U.S. dollars to 6.6 billion dollars, England said.

    Bush announced in January that over 20,000 additional U.S. combat troops would be sent to Iraq to help quell sectarian violence in the war-torn country, but the plan has met strong resistance from the Democrats-controlled Congress.

    Currently there are over 140,000 U.S. troops in Iraq, and more than 3,000 American soldiers and tens of thousands of Iraqis have been killed in the country since the U.S. invasion in March 2003. ¡¡