The US has spent nearly $3 billion in the fight against Daesh, the Pentagon said in an update.

As of June 18, the total cost of operations since August is $2.91 billion, US-funded Radio Sawa quoted the Pentagon as saying.

The average cost per day of $9.2 million has ticked up slightly since the last update in early June, it added. At that time, the average daily cost was about $9.1 million.

A bulk of the expenses, 54 percent, has been spent on airstrikes, said the Defense Department, which broke down the average costs from August through mid-June.

Just under a quarter has been spent on weapons, and the rest has been spent on missions involving military carriers and other operations.

In August, the US began launching airstrikes against the terrorist group in Iraq and expanded the airstrikes to Syria September.