The US has spent more than $2.7 billion on the war against Islamic State (formerly known as Isis) militants in Iraq and Syria since bombings began last August, the Pentagon says.
Releasing a detailed breakdown of the costs for the first time, the Defence Department showed that the US Air Force has borne two-thirds of the total spending, or more than $1.8 billion.
The average daily cost is more than $9 million, with combat, reconnaissance and other flights eating up more than $5 million a day.
The data also provided a rare look into often secret special operations costs, which totalled more than $200 million since August.
The release of the spending totals came as Congress debated and rejected legislation that would have banned spending on combat operations until policymakers passed a new war powers resolution.
Military operation costs have grown since air strikes began in Iraq in August, expanding to Syria the following month.
Other total costs include $438 million for the navy, including fighters and other ship support; $274 million for the army, which has trainers and special forces troops on the ground; $16 million for military pay; $646 million for munitions; and $21 million for intelligence and surveillance operations.
Meanwhile, the body of an American who died fighting with Kurdish forces against IS in Syria has been handed over to his family at a Turkish border crossing, a Kurdish official said.
Hundreds of people turned up in the Kurdish town of Kobani to bid farewell to Keith Broomfield before his body was handed to family at the Mursitpinar gate, said Idriss Naasan.
Broomfield, from Massachusetts, died on June 3 in battle in a Syrian village near Kobani, making him probably the first US citizen to die fighting alongside Kurds against IS.
The fight against IS has attracted dozens of Westerners, including Iraq War veterans who have made their way back to the Middle East to join Kurdish fighters, who have been most successful against the extremist group.
The Britain-based Syrian Observatory for Human Rights, which keeps track of Syria’s war, said more than 400 foreign fighters have joined the People’s Protection Units, known as the YPG, to fight IS in recent months, including Europeans, Americans, Australians and thousands of Kurdish fighters from Turkey and Iran.
Previously, a British citizen, an Australian and a German woman were killed fighting with the Kurds.
The YPG has posted a video that showed Broomfield saying he was in Syria “to do what I can to help Kurdistan. With everything that’s been going on, it seems like the right thing to do”.
“I just want to help the cause any way I can,” he said.