The cost of the US-led war against the Islamic State (Isis) militant group has totalled at least $780m, according to a new estimate, as US drones and warplanes continued to attack Isis positions in Iraq and Syria on Monday.



The US defense secretary, Chuck Hagel, said on Friday that the US military is spending up to $10m a day and is likely to request more money from Congress to fund a war whose duration is uncertain. In August, before the US expanded strikes against Isis into Syria, the Pentagon estimated its daily war costs at $7.5m and has yet to provide a more precise estimate.

The Center on Strategic and Budgetary Assessments (CSBA), a thinktank influential with the Pentagon, estimated on Monday that the air war has already cost between $780m and $930m between 8 August, when it began, and 24 September.

Congress has not voted on going to war, outside of authorizing the military to train a proxy Syrian rebel ground force, and will not do so until after the November midterm elections at earliest.

The CSBA priced out estimates running a gamut of options proposed by politicians, retired military officers and pundits for escalating the war. What it called a “moderate level of air operations”, involving 2,000 “deployed ground forces” – a level slightly higher than the 1,600 ostensibly non-combat security and “advisory” US forces in Iraq now – would total as much as $320m each month and $3.8bn annually.

Should the US deploy a ground force of 25,000 US troops, as advocated by Iraq surge architect Frederick Kagan, annual costs would run “as high as $13bn to $22bn”. An air campaign with a higher operational tempo and a 5,000-troop deployment would cost between $350m and $570m per month and $4.2bn to $6.8bn each year.

General Martin Dempsey, the chairman of the joint chiefs of staff, opened the door to US ground combat alongside Iraqi and Kurdish forces in congressional testimony earlier this month. He and Hagel on Friday anticipated asking Congress for additional money in the military’s baseline budget, which already stands at about $500,000, excluding nearly $59bn in requested war funding, mostly for Afghanistan.

That war funding is “gas money”, Dempsey said, above the strains that a new and budgetarily unanticipated war are likely to have on the funding assumptions of the military services.

Joint Chiefs of Staff Chairman General Martin Dempsey, right, and Secretary of Defense Chuck Hagel. Photograph: T.J. Kirkpatrick/Getty Images

Air strikes in Syria now occur daily, as do their counterparts in Iraq. On Monday, the US Central Command announced that it conducted eight strikes in Syria on Sunday night and Monday, including against an Isis-held airfield near Aleppo. Jennifer Cafarella, a researcher with the Institute for the Study of War – a thinktank operated by the Kagan family – said the airfield was likely the Jarrah airbase, previously in the hands of competitor Syrian militant groups.

Central Command said aircraft from the United Arab Emirates and Jordan participated in the most recent rounds of Syria strikes. Those strikes also targeted Isis armed vehicles, an air-defense transport vehicle, a storage facility and a training camp in positions ranging from Deir el-Zour, Raqqa and Manbij.

Unilateral US airstrikes in Iraq also occurred near Kirkuk, Sinjar and an unspecified location in northwest Iraq, targeting what Central Command said were Isis armed vehicles.

While the US attempts in Iraq to foster Iraqi and Kurdish ground forces to reclaim territory from Isis, its plan to raise a Syrian proxy force is not expected to field its first units for nearly a year. Dempsey estimated Friday that rolling back Isis in Syria will require a proxy force of between 12,000 and 15,000.Почему бы и нет

The White House requested $500m to train and arm Syrian rebel forces, but it is unclear how many rebels that total will initially fund. The Pentagon estimates it can train up to 5,000 “vetted” Syrians within a year, a figure suggesting the training might run to $1.5bn for a 15,000-strong force, excluding the costs of keeping that force viable in the field.