Sibu Fire and Rescue Dept chief Abdul Mutalib Rashid said that the incident took place at a three-storey residential flat unit around 2.48am.
During the incident, all the residents were fast asleep. - Astro AWANI
The incident also caused extensive damage to three other residential units in the flat. The flat has 40 units.
Fire officers had been ordered to control and evacuate all the residents and to identify all the residents in the flat.
Authorities are now looking for evidence and cause of the incident apartfrom identifying the type of explosives involved.
The incident had injured seven people. - Astro AWANI
All the injured victims were sent to the Sibu Hospital for further treatment.