A blaze at an Islamic boarding school in the Malaysian capital of Kuala Lumpur has killed at least 23 people, most of them teenage boys.  

The fire broke out at around 5.40am in a top-floor dormitory of the three-storey building, firemen said, where most of the students, aged between 13 and 17, were sleeping in bunk beds, with many of the windows covered by metal grills.

Two teachers were also killed in the fire at the Darul Quran Ittifaqiyah, police said. Most of the victims died from smoke inhalation.

The disaster has renewed calls for greater scrutiny of so-called "tahfiz" schools, where students learn to memorise the Quran. They are unregulated by the education ministry, being the responsibility of the religious department.

At least 30 fires at such schools have been reported this year, a local government minister told reporters, adding that the Kuala Lumpur school should not have been in operation. He did not elaborate on the previous fires.

The deputy director of the fire department operations said officials were investigating the fire but it was likely caused by a short circuit or a mosquito repellent coil.

The parents of one of the fire victims outside the Darul Quran Ittifaqiyah school

The dormitory had only one entrance, leaving many of the victims trapped, he said. At least one window was unbarred.

The deputy director said: "The building was surrounded by metal grills that could not be opened from the inside. The students, after realising the fire and heavy smoke, tried to escape through the window.

"But because of the grills, they could not escape."

He said the school had submitted a request for fire safety approval but no new checks had been carried out as the request was still being processed.

A man identified only as Hazin, who lived next door to the school, said his son called the fire department after they heard screams and saw the flames.

"The children were crying for help, but I couldn't help them as the door was already on fire," he told Reuters.

"I only managed to save a few of the kids who jumped out the window."

Viewed from outside, the only tell-tale signs of disaster were the blackened upper-floor windows, otherwise the tin-roofed building appeared unscathed, with a Malaysian flag hanging limply from the yellow wall.

Only inside did the intensity of the inferno become clear. The dormitory was blackened, lined with the charred frames of bunk beds.