Three people were injured in the blaze, which erupted at the summer camp at Hwasong in Kyonggi province 60 kilometres southwest of here at around 1.40 am. Firemen mobilised more than 90 fire engines and brought the inferno under control after about three hours.

Although the cause of the blaze was not immediately known, fire officers were investigating ``a short circuit or burning mosquito repellent coils,'' a firefighter said.

``The death toll was high because most children were asleep on the top floor of the building that caught fire,'' a senior fire officer told AFP by telephone. ``They were mostly charred or suffocated on the third floor''. Most of the victims were aged around six and were from nursery schools in southern Seoul, fire officers said.

Around 520 children aged between five and seven wereasleep at the camp, called Sealand, when the fire started in the three-storey building of which the top two floors were made from shipping containers lined with flammable materials including wood.

The children had been sent to the camp by their parents for a one-to-two day break during the summer school holidays, officials and parents at the scene said.

Horrified teachers, who were sleeping in a nearby building, stood by helplessly as the fierce blaze consumed the screaming children's dormitories. ``The other teachers and I heard the children screaming so we rushed out to see smoke and flames coming out of the rooms where the children were sleeping,'' said Kim Jae-Hoon, a teacher at the camp.

``We tried hard to rescue them but the fire spread quickly through the building.The flames were so huge that we couldn't get to them. It took a long while fr the fire engines to get here,'' he told reporters.

Firefighters sifting through the charred wreckage of the building in search of further corpses orsurvivors said they did not expect to find more victims.

The building contained 59 childrens' dormitories. Eighteen of the victims were from one kindergarten south of the capital, who were sleeping on the third floor. At least one teacher was injured.

``The staircase linking the second floor with the third floor turned into a hell, with screams and moans from panicky children falling over themselves in a stampede,'' said Kang Kwon-Su, a kindergarten teacher. A firefighter said the structure had only two narrow staircases and a few fire-extinguishers which did not work.

One whimpering five-year-old with burns to her legs, said: ``I was awakened because it was too hot. The light in the room was out. Scared, I left the room and found Miss Lee (a nurse)''.

While officials said most of the victims were either burned to death or died of smoke inhalation, media reports said the fatalities were caused by the collapse of the building, insulated with Styrofoam and plastic materials which exuded poisonousgases.

Three children had still to be identified.

The injured were rushed to Namyang Dongseoul hospital in Hwasong, while other survivors were evacuated to safety in nearby homes and buildings. The fire marks South Korea's first major disaster this year and came exactly four years after the collapse of a Seoul department store which killed hundreds.

A construction site inferno killed 27 people and left 16 injured in the southern port city of Pusan in October last year.