The move comes after President Obama last week formally implemented a new round of American sanctions on Iran passed by Congress in August.
The Obama administration credits itself with working with Europe to get it to ban oil imports for the first time and argues that just pursuing unilateral sanctions is a doomed effort.
Iran, along with the al Qaeda attack in Libya that killed U.S. Ambassador Christopher Stevens, are the dominant foreign policy focus points in the fall election campaign.
GOP candidate Mitt Romney says Obama has not made it clear enough that the United States will do everything necessary to prevent an Iranian nuclear bomb and that the White House has snubbed Israeli Prime Minister Benjamin Netanyahu on the subject.
The Obama campaign says it is closely coordinating with Israel and is keeping military strikes as an option while trying to avoid another Mideast war.