Lieutenant General Charles Brown told reporters at the Dubai International Air Chiefs Conference that the reduction in air strikes was due to weather and to a slowdown in activity on the ground and not due to the start of Russian air strikes in the region, the report says.
He said both government forces and insurgents were increasing their ground movements, which could create more opportunities for the United States and its allies to carry out more air strikes against Islamic State targets.
"If they're not out and about, it's harder to strike, particularly for an adversary that may wrap themselves in the civilian population," he said.
Brown also rejected criticism that the United States was not using air strikes as much or effectively as possible, saying coalition forces were striving to avoid civilian casualties that could help recruitment for Islamic State.
He also noted that the sheer number of air strikes was less of an indicator than the targets hit and the number of weapons used.