An explosion took place at a shipbuilding plant which is located 37 kilometres west of the port of Bandar Abbas near the Strait of Hormuz.
Citing local media, Sputnik International reported that at least three staff in the Iranian defence industries were killed in the blast that occurred in an under construction submarine in Southern Iran.
A local website reported that the blast happened after three batteries on the vessel exploded.
"Three Defence Ministry staff were martyred after a submarine battery exploded at the Shahid Darvishi shipyard in (the Gulf port of) Bandar Abbas..., which builds and repairs military ships and submarines," the Islamic Republic of Iran Broadcasting reported.
More details are awaited.
According to Sputnik, Tehran has been developing light and heavy weapons ranging from mortars and torpedoes to tanks and submarines.