According to preliminary data from Narayanganj Fire Service's Deputy Assistant Director Abdullah Al Arefin, as quoted in the Dhaka Tribune newspaper report, gas leaked out from underground pipes and accumulated inside the mosque and then detonated "due to sparks when someone tried to switch [one of the six] air conditioners or fans on or off".
There was a 7-year-old child among the deceased, according to the news outlet.
More than 15 people are reportedly still being treated from burns and other injuries at the Sheikh Hasina National Institute of Burn and Plastic Surgery in Dhaka, the capital of Bangladesh. All of them are in critical condition, Partha Shangkar Paul, a resident doctor at the institute, was cited in the report as saying.
The explosion occurred on the evening of Friday as people gathered in the mosque for evening prayer. The local fire department and police launched an investigation into the incident.