WASHINGTON (Reuters) - The U.S. wars in Iraq and Afghanistan could cost taxpayers a total of $2.4 trillion by 2017 when counting the huge interest costs because combat is being financed with borrowed money, according to a study released on Wednesday.

U.S. soldiers rush a patient towards a Medivac Blackhawk helicopter of the Charlie Company 2-227, Aviation Battalion called "Witchdoctors" after lading at the forward operating base Liberty camp in Baghdad October 5, 2007. REUTERS/Fabrizio Bensch

With President George W. Bush indicating a large contingent of U.S. troops likely will be engaged in Iraq and Afghanistan for many years to come, the nonpartisan Congressional Budget Office estimated the total tab for the wars from 2001 through 2017.

CBO estimated that interest costs alone from 2001-2017 could total more than $700 billion.

So far, Congress has given Bush $604 billion for the two wars, with about $412 billion spent in Iraq, according to CBO, which is Congress’ in-house budget analyst. In Iraq alone, the United States is spending about $11 billion a month, with costs escalating.

Bush is seeking another $196 billion for combat in Iraq and Afghanistan through September 30 and Congress is expected to debate that request over the next few months.

CBO estimated that between 2008 and 2017, the wars could cost slightly more than $1 trillion, assuming overall troop strength is cut to 75,000 by 2013.

Currently, there are about 170,000 U.S. troops in Iraq and another 26,000 in Afghanistan.

Finance charges for the money already spent on the war will total $415 billion from 2001 to 2017, according to CBO. For the next decade, “interest outlays would increase by a total of $290 billion over that 10-year period,” CBO told the House Budget Committee, which is reviewing long-term war costs.

“To put it all on our credit cards with no accountability, with no plan to pay for it, I think is the height of irresponsibility,” said Rep. James McGovern, a Massachusetts Democrat who serves on the budget panel and is an outspoken war critic. “It will be just one more toxic legacy of this disastrous war we will have to leave our kids to clean up.”

With national elections about a year away and public discontent with the Iraq war running deep, Democrats are highlighting the huge costs of the Iraq war as they seek $22 billion more than Bush wants for domestic social programs such as health care and education.

Bush has vowed to veto the added funding.

CBO estimated that of the $2.4 trillion long-term price tag for the war, about $1.9 trillion of that would be spent on Iraq.