They watched, helpless and in horror, as flames gutted the top floor of an Islamic religious school and took the lives of 23 people, most of them young boys.

Those images, the smell of thick smoke, and the frantic cries for help from the victims trapped behind barred windows would stay with them for a very long time, say residents in Jalan Datuk Keramat in Kuala Lumpur where the tahfiz, or religious school, is located.

A 57-year-old man, who did not want to be named, had woken up early and was performing his morning prayers when he smelt smoke.

"I didn't think much of it as I thought it was because it was hazy outside," he told The Straits Times yesterday.

"But when the cries became more apparent, like many people were shouting at the same time, I looked out of my window," he said.

He was shocked to see the religious school on fire.

"I immediately rushed out to help but there wasn't much that we (neighbours) could do," he said, his voice and hands trembling.

He admitted it was hard to block out those cries for help in his head.

"I couldn't sleep at night. I keep on thinking there must have been something that we could have done to save them," he said regretfully.

"If only I had known about the fire earlier, maybe I could have done something... it's such a terrible feeling."

Ms Nor Asfi Ilya, 39, is also finding it difficult to move on from the tragedy that killed 21 students and two wardens at the Darul Quran Ittifaqiyah Tahfiz, on Thursday.

Many of the bodies were found piled one on top of the other and burnt beyond recognition.

"I doubt we can forget this. My family is very much affected and we're not even the families of those who perished," she said.

"I can only imagine the grief the families are going through. My prayers are with them but something needs to be done to prevent a repeat of this tragedy."

A 29-year-old widow, Mrs Mashawani Mohamed Shahid, lost all her three sons - Muhammad Syafid Haikal, 13; Muhammad Hafiz Iskandar, 11; and Muhammad Harris Ikhwan, 10 - in the fire.

The Star's Malay portal, mStar, quoted Mrs Mashawani's cousin, Ms Rosnani Mohd Nor, as saying: "Our family is grieving, especially the mother… I hope she will stay strong through this trial."

Ms Mas Aliza Ali Bapoo, 22, a relative of the victims, said the middle child, Hafiz Iskandar, had called on Thursday to say he wanted to go home.

"We planned to take the three of them on Saturday but did not expect all of them would perish.. we are too shocked.

"I feel the pain most, as I have been the one handling their transport to and from the tahfiz school since they began studying there in January," she was quoted as saying.

Nadirah H. Rodzi