Pentagon spokesman Peter Cook said Abu Waheeb and three others died when their vehicle was hit on May 6 near Rutba, the BBC wrote.
"It is dangerous to be an Isil leader in Iraq and Syria nowadays," Mr. Cook added, using an acronym based on the former name of IS.
Abu Waheeb has falsely been declared dead on several previous occasions.
The Pentagon described Abu Waheeb, who is also known as Shakir Waheeb, as the IS "military emir for Anbar province."
Read alsoIslamic State gunmen partially seize gas field east of HomsBorn in 1986 and a former computer science student, Abu Waheeb was often described on monitoring sites as a rising star among IS.
A former member of al-Qaeda in Iraq, a precursor of IS, he was arrested by U.S. forces in Iraq in 2006 and sentenced to death but escaped prison in 2012.
The following year, he gained notoriety for killing a group of Syrian lorry drivers travelling through Iraq.
An international coalition led by the U.S. has been carrying out air strikes on IS positions in Iraq since 2014, when the group seized large swathes of territory.
