The announcement was made today by the country's prosecutor-general, Qorban Ali Dori-Najafabadi, who added that a total of seven people have been arrested in connection with the bombings.
The semi-official Mehr news agency reports that the "televised confessions " of one of the "elements" involved in the bombings will be aired by the end of the week. It did not specify whether the confession was made by one of the two men sentenced to death.
Eight people were killed and dozens were wounded in the blasts on 24 January. Iran has blamed foreign elements, especially from Britain, of being behind the attack.