KUALA LUMPUR, Sept 15 — Two gas canisters found at the tahfiz school here where a fire broke out yesterday, killing 23, has raised suspicion and questions about the cause of the blaze.

Utusan Malaysia reported surviving witnesses as saying that two yellow gas canisters were seen outside the students’ dormitory at Tahfiz Darul Quran Ittifaqiyah in Kampung Datuk Keramat here, even though gas canisters are normally not placed on the higher floors as the students are not allowed to cook.

The Fire and Rescue Department also reportedly confirmed the presence of the gas canisters, and has ruled out any electrical fault as causing the 5.40am fire, which spread quickly and killed 21 students aged 11 to 17 and two wardens who were trapped on the upper floors of the building due to metal grilles placed on windows.

"According to surviving witnesses, the fire started from outside the dormitory door which caused the victims to be trapped inside. The two gas canisters may have made the fire bigger and caused it spread faster,” the Kuala Lumpur Fire and Rescue Department director Khirudin Drahman said.

A staff of the tahfiz school, Mohd Arif Awardi, also reportedly described the gas canisters’ presence as "peculiar” because the canisters were not there when he checked the area at 11pm the previous night.

"Gas canisters are normally placed in the ground floor of the school, and they are green coloured canisters, not yellow,” he said.

Yesterday’s fire at the school for Quranic memorisation was the deadliest in almost three decades since the 1989 blaze at a religious school in Kedah that killed 27 students.