A unilateral U.S. oil embargo on Iran is expected to remain in place even if a long-term nuclear agreement between Tehran and six world powers is reached that includes an easing of international sanctions, a U.S. official said on Thursday. The embargo pre-dates the decade-long nuclear dispute with Iran. Washington cut off diplomatic ties with Tehran during a hostage crisis shortly following the 1979 Islamic Revolution and began imposing sanctions around the same time. “The American domestic oil embargo is expected to remain in place even if a comprehensive agreement is reached,” the U.S. official told Reuters on condition of anonymity. Western diplomats say U.S. companies would be unhappy about being left out if European Union and U.N. sanctions are lifted, allowing non-U.S. firms to resume business with the Islamic Republic. Iranian officials say they would have no problem with American oil companies returning to Iran. […]