Passengers trapped on a burning train were able to make anguished last phone calls to relatives, reports from South Korea say.

Families have been describing how they heard from their loved ones after flames engulfed carriages in an underground tunnel in the city of Daegu.

I told her to just break open a window and get out Kim Bok-sun, mother of victim

More than 120 people died in the mid-morning arson attack on the train in the centre of the city.

Relatives flocked to the station and to hospitals hoping for good news.

But many passengers remain missing and many victims are said to be burnt beyond recognition.

'Why?'

Chung Sook-jae, 54, rushed to the scene after her daughter, 26-year-old Min Shim-eun, telephoned her husband to say she was suffocating. Then the line went dead.

"She never caused any problems," a crying Mrs Chung told the Associated Press news agency.

Survivors phoned relatives, but some people could not get their loved ones to answer calls

"She was a good kid. Why does this have to happen her?"

Mrs Chung said she feared the worst. "If she's not out by now, she's probably dead. What am I going to do if her body is all burnt out of recognition?"

Similar stories were being recounted across Daegu.

Kang Yeon-ju, 21, phoned her mother to say there was a fire on the train and that the doors would not open.

"I told her to just break open a window and get out," her mother, Kim Bok-sun, told Associated Press.

She called her daughter a few minutes later, Mrs Kim said, "but she never answered the phone".

'Help me'

One man, whose wife was trapped by the inferno at the tail end of the morning rush hour, told South Korean television he had received a desperate call from her mobile phone.

There would have been hardly any time to escape Lee Hyong-kyun, rescue official

"Help me," he quoted her as saying. "There's a fire on the subway. The door is locked."

Rescue official Lee Hyong-kyun told Reuters news agency that many of the dead stood no chance once a man lit a carton of some flammable liquid.

"If you ignite a flammable liquid like gasoline inside a closed space, you'll get is something very close to an explosion," he said.

"There would have been hardly any time to escape."

He said the fire ignited seat fabric and floor tiles.

Black smoke and acrid fumes poured out of subway ventilation holes, hampering the efforts by more than 3,000 rescuers sent to the scene.

Firefighters clad in orange protective suits and oxygen tanks raced into the subway.

They brought out survivors blackened by soot - as well as the bodies of those who did not survive.

"I brought out four bodies and they were already dead, lying on the stairs," Park Chang-shik told Associated Press.