Seoul - South Korean police said on Sunday that they had requested arrest warrants for four people on charges of involuntary manslaughter after Saturday's fire at a karaoke bar that killed 55 people in the port city of Inchon.
"We have asked for warrants for the arrest of four workmen...," said a police investigator, noting renovation had been taking place in the building where the fire broke out.
"We expect the arrest warrants to arrive on Monday," he said.
The investigator, who asked not to be identified, said the four were in police custody.
The fire raced through a four-storey shopping centre on Saturday night, killing 55 people and injuring about 75, the worst fire in Korea in more than two decades.
Most of the victims were teenagers who were drinking illegally, police said.
A teenager who had been rescued in critical condition died on Sunday.
At least 19 of the injured remained in critical condition in area hospitals after inhaling poisonous fumes, doctors and nurses said.
"Some of our critical patients (from the fire) cannot breathe on their own," said a doctor in charge of an intensive care unit at an Inchon hospital. "You could say the fumes burnt their lungs."
A fire brigade official said the blaze apparently started in a basement karaoke bar in the shopping centre in Inchon, 50 kilometres west of Seoul, at about 7pm (1000 GMT).
The bar was undergoing renovation and was empty, but the fire soon spread to a bar and another karaoke on the floor above where more than 120 people were drinking beer and singing, he said.
Firefighters said they saw what appeared to be empty cans of flammable paint thinner on the floor of the karaoke bar under renovation, where the fire originated.
Police said they had yet to identify more than 25 of the dead as most of the victims were under age and were not carrying any identification.
"Most of them were high school kids who had flocked to the bar to drink beer and sing after an autumn festival at their schools," said a police official at the Inchon headquarters.
"We are mostly relying on the parents whose children are missing to come down to various hospitals to try and recognise them."
Hundreds of parents desperately searched for their missing children, visiting one hospital after another throughout the night, television reports said.
"Where is my daughter? I can't find my daughter," a distraught mother cried on television.
Karaoke bars, known as "singing rooms", are popular in Korea.
They are usually a large area divided into small cubicles equipped with sing-along karaoke machines.
Fire officials have often said the cramped rooms are potential fire hazards.
The Inchon fire is the worst such disaster in South Korea in 25 years, media said.
The death toll exceeded that of a fire in April 1995 when women at a rehabilitation centre in Yongin, 40 km south of Seoul, set fire to their dormitory in an attempt to escape, killing 37 women locked in for the night.
Two years earlier, fire swept through a mental hospital in the central city of Nonsan, killing 35 psychiatric patients, many of whom were shackled hand and foot.
Last June, 19 kindergarten children and four adults died in a dormitory blaze at a summer camp near the west coast city of Hwasung. - Reuters