Washington - President Barack Obama will ask lawmakers on Friday for an additional $3.2bn to pay for the war against the Islamic State of Iraq and Syria (ISIS), including funds to train and arm Baghdad government forces, officials said on Thursday.
The funds will help cover the cost of replacing bombs in the weeks-long US-led air campaign against ISIS jihadists and assistance for Iraqi army troops and Kurdish forces battling ISIS on the ground, two defence officials told AFP.
The air war in Syria and Iraq, which commanders say could last years has involved thousands of sorties and hundreds of bombing raids, at a daily cost of $8.3m, according to the Pentagon.
But independent analysts say the price tag is higher if the full costs of the air operations are taken into account, particularly numerous flights by sophisticated surveillance aircraft.
According to the Pentagon, the air war, dubbed Operation Inherent Resolve cost $580m as of 16 October.
The proposed funding also would pay for the roughly 600 US military advisors who are working with Iraqi and Kurdish forces in Baghdad and Arbil, as well as about 800 other American troops providing security for the US embassy and Baghdad airport.
The request to approve money for the air campaign follows comments by Obama on Wednesday saying he will ask Congress to approve new legal authority for the war. The White House had said previously there was no need for Congress to weigh in on war power authorities.
Both moves will offer Congress a chance to debate the president's war strategy, amid criticism from lawmakers across the political spectrum questioning the administration's approach.
The funding request will come as an amendment to the Pentagon's de facto war budget, known as the overseas contingency operations (OCO) fund, officials said.
In June, the administration requested $58.6bn for the war operations budget for the current fiscal year, which began 1 October, but since then the United States launched a major air campaign in Iraq on 8 August and in Syria on 23 September.
The OCO fund is often described as a "credit card" to cover the cost of wars and is separate from the regular defence "base" budget that is supposed to cover weapons programmes, wages and other items not directly associated with fighting wars.
At the current pace of air strikes, the widening war against the ISIS group will cost more than the 2011 Libya conflict, which came to one billion dollars, and could add up to several billion dollars for one year, experts say.
The rising cost still pales in comparison to the astronomical price tag for the protracted counter-insurgency campaigns in Iraq and Afghanistan over the past decade, which came to trillions of dollars.