All of them died at Sheikh Hasina National Institute of Burn and Plastic Surgery in Dhaka while undergoing treatment there till Saturday afternoon, confirmed Dr. Samanta Lal Sen, coordinator of the institute, Dhaka Tribune reported.
"Now 20 victims are undergoing treatment at the hospital," he added.
So far, 12 bodies have been handed over to their relatives, officials said.
Dozens of people were injured in the blast that took place around 9 pm on Friday at the Baitus Salah Jame Mosque located in the West Tolla area in the Sadar Upazila's Fatullah neighborhood.
According to the local police, the blast occurred when the Isha prayers were about to end.
Narayanganj Fire Service and police have already initiated an investigation into the blast while Titas Gas Transmission and Distribution Company Limited formed another probe body to look into the incident.
FA/PR