The plan does not indicate whether the US would be willing to invade, but aids said that the number of troops would not be enough.
US President Donald Trump has received a plan from some of his top aids that suggests sending up to 120,000 troops to the Middle East if Iran attacked US troops.
The troops would also be sent if Iran accelerated work on their nuclear project, the New York Times reported, towards what Washington would classify as progress on building a nuclear bomb.
The plan, however, revised by hard-line aide to Mr Trump and national security adviser John R Bolton, does not call for a land invasion of Iran, with aides saying an invasion would require significantly more troops.