The State Department has sent a cable to all consular posts specifying how the embargo against Iran affects employers considering employing an Iranian national. The basic rule is that it is unlawful for an employer to issue an offer of employment to an Iranian national. Posts are instructed to deny employment-based visas for Iranian nationals residing in Iran. Iranians living in the US would not be covered.  

Employers do not violate the sanctions rules by employing Iranians residing permanently in the US. And it is not a violation to offer to hire or to actually employ an Iranian in a dual-intent visa category such as H-1, L-1, E, or R visa status). However, it would be a violation to offer employment to an Iranian national in the US in a visa category requiring the applicant to show an unabandoned residence abroad such as B or F visa status.

The State Department notes that determining whether someone is a resident in Iran is not necessarily clear cut and should be determined based on the totality of the circumstances. The posts provides the example of a undergraduate student who makes visits home during holiday breaks. That person would be a resident. By contrast, a graduate student who purchased a residence in a third country, established a family there and enrolled children in school there would not be considered residents of Iran. Also, merely holding permanent residency status in another country is not adequate if the person does not actually reside there or maintain close ties. On the other hand, a temporary resident of a third country may work if the applicant has actually lived in a place for some time.