US companies can establish themselves in Iran's oil projects, Petroleum Minister Bijan Namdar Zanganeh said on Tuesday.
"If US companies want to work in Iran's oil industry, there will be no restriction for them from the Iranian side," Xinhua news agency quoted him as saying.
However, "no American company has directly applied to work in Iran's oil industry so far", Zanganeh said.
The remarks followed US President Donald Trump's order to restrict immigration from seven Muslim-majority countries including Iran.
The National Iranian Oil Co in January invited 29 companies from 14 countries to submit tenders for the country's oil and gas projects.
The move represents a big step to open up Iran's oil and gas fields to Western investment, the country's Petro-Energy Information Network said.