Bijan Zanganeh's comments on Tuesday come as Americans and U.S. companies are still barred from directly doing business with Iran. That's even with the 2015 nuclear deal being in place.
Zanganeh was quoted as saying: "If they want to, we are ready to negotiate American companies about development of oil and gas resources."
His remarks were reported by Iran's state-run IRNA news agency.
He added: "We have not closed doors" to American companies.
Trump last week refused to re-certify Iran's compliance with the nuclear deal with world powers, and criticized Europeans for their participation in Iran's energy projects. French oil giant Total SA has entered the Iranian market following the deal.