Reports say 20 people were retrieved from under the ruble including 13 who received outpatient treatment at a hospital and then discharged.
A 75-year-old woman who was wounded, later succumbed to her injuries.
A firefighter at the scene told the IRIB the explosion was so powerful that it destroyed five nearby buildings as well.
The firefighter did not rule out the possibility of people remaining trapped under the debris.
The blast has been blamed on a gas leak.
