Iran has started to sell oil to private buyers through its energy exchange for the first time as part of efforts to counter the imminent return of U.S. sanctions.
The sanctions are aimed at stopping the country's key crude exports and follows President Trump's decision to walk out of the 2015 Iran nuclear deal.
They are due to come into effect on November fourth.
Only 280,000 barrels were sold on Sunday out of one million offered, and they went for just under 75 dollars a barrel.
However, Tehran says it is confident the U.S. sanctions will not reduce its oil exports to the level of less than one million barrels per day.