"The ship's crew are fixing the defect and the vessel is in a stable condition from a safety standpoint. Fortunately, the ship's crew are in a safe condition," IRNA quoted Akbar Jabal-Ameli, technical director of the state-run National Iranian Tanker Company, as saying.

The report identified the tanker as HELM. A vessel with that name is among individuals, companies and vessels which are under U.S. sanctions, according to the U.S. Treasury's website.

Iran has one of the largest tanker fleets in the world, but Tehran is running short of options to replace its aging tankers and keep oil exports flowing because renewed U.S. sanctions are making potential sellers and flag registries wary of doing business with Tehran.