Kuala Lumpur police chief Amar Singh said there had been allegations that the school in question may not have the necessary permit.
Twenty-three people, including 21 students, were killed when a fire tore through the religious school located in Datuk Keramat here early today.
Amar said that six other students who were injured are currently receiving treatment at Hospital Kuala Lumpur.
Families of the children who perished in the blaze were asked to congregate in the surau next to the school to identify the bodies.
According to AFP, the blaze broke out at the Darul Quran Ittifaqiyah tahfiz school, located on Jalan Keramat Ujung, just before dawn.
Firefighters rushed to the scene and the blaze was put out within an hour but not before it had wreaked terrible devastation.
A fire department official at the scene said that the blaze broke out in a bedroom before dawn, and firefighters from a nearby station were on the scene within minutes.