Caroline Bain, chief commodities economist at Capital Economics, told the BBC's Today programme that Iran had been increasing oil production over the course of this year despite US sanctions.
"The US seems to have turned a blind eye to a steady increase in Iranian production, that... is going to be more difficult for the US to ignore going forward from here," she said.
Overall, Ms Bain said Capital Economics expected demand for oil to exceed supply in the final three months of the year and "that should support higher prices".