"There is quiet diplomacy going on but it's hard to say when it will be resolved," he said with regard to the campaign to remove U.S. sanctions.

In an interview with petroleum Argus, Dunham said the bottom lines was that progress was being made with the Clinton administration but it "may take a new leader to come out and say let's put politics behind and do what's best for both countries."

The chief executive, who has been an outspoken critic of U.S. sanctions against Iran, has not been shy about wanting to put Iran in conoco's upstream portfolio. "everyone we admire for their intellect says it's bad policy," he said.

Dunham also serves on the influential U.S. National petroleum council, advising the white house on long-term energy strategy, but has been unsuccessful in four years of campaigning to change policy on sanctions.