An Iranian senior naval official is quoted as saying the Islamic republic has taken the "initial stages" toward designing its own nuclear-powered submarine.
Admiral Abbas Zamini, deputy naval chief for technology, was quoted by Iran's Fars news agency on June 12 as saying Iran needed the vessel to conduct "very long-distance operations."
No further details were given about the aims of the program.
Only the United States, Russia, China, France, and Britain have successfully built nuclear-powered submarines.
India says it is currently developing one.
Iran is at odds with much of the international community over its nuclear development program, which the United States and its allies suspect is aimed at making nuclear weapons.
Tehran maintains the program has exclusively peaceful aims and has no weapons intent.
Based on reporting by AFP and AP