The Pentagon has spent as much as $US1.
1 billion ($A1.19 billion) on US military operations against Islamic State militants in Iraq and Syria since the mission began in mid-June, including more than $US62 million alone in navy airstrikes and Tomahawk cruise missiles.
US Central Command said the navy has dropped about 185 munitions, including 47 cruise missiles launched from ships in the region.
Central Command, in data released on Monday, said US air force fighter jets have far exceeded those numbers, launching close to 1000 munitions.
The $US62 million is only for navy munitions.
No costs were provided for air force munitions.
Arab and other allied countries have carried out only about 10 per cent of the nearly 2000 air raids against the Islamic State group in Iraq and Syria since early August, US defence officials also said on Monday.
US warplanes have conducted 1768 air strikes since August 8 while other coalition aircraft have carried about 195 air raids against the IS jihadists, according to the latest tally through Sunday, defence officials, who spoke on condition of anonymity, said.
The numbers, which for the first time shed light on the participation of Arab coalition partners, reflect the dominant role of the US military in the air campaign.
But Pentagon officials have insisted the role for Arab and European partners is likely to grow over time.
The Arab states involved in the operation in Syria – Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates – have been reluctant to divulge details of their participation in the air strikes.
France, Belgium, Britain, Denmark, the Netherlands and Australia have committed aircraft for the effort in Iraq.
The Pentagon has struggled to come up with specific cost figures for the Iraq and Syria operations.
Officials said it has cost an average of $US7 million to $US10 million daily since June.
The costs of the operations began at a much lower rate in June then escalated as airstrikes began in northern Iraq on August 8.
In late August, the Pentagon said the cost was an average of $US7.5 million daily.
The airstrikes were expanded to Syria in September, prompting the latest, higher average estimates.
There are currently more than 1300 US troops in Iraq, including security personnel, staff at two joint operations centres in Baghdad and Erbil, and advisory teams that are working with Iraqi brigades and headquarters units.