Grieving relatives have been trying to identify charred bodies from the wreckage of a Spanish jet, which officials said had been forced to abort a take-off earlier in the day at Madrid airport due to mechanical problems.

Airline officials declined to comment on possible causes for Wednesday's tragedy in which 153 people were killed.

But the officials said that Spanair Flight JK5022 had been delayed due to a problem with the air intake heating system before it attempted a second take-off for its flight to Las Palmas in the Canary Islands.

Survivor Ligia Palomino said: "They supposedly fixed the problem which the pilot later said was with the air conditioning and then we took off.

"The plane was wobbling from one side to another. Then I began to suspect we would crash. I don't know what happened next. I was in a sort of river and saw people, smoke, explosions - which I think woke me up."

Rescue workers said the only passengers to survive Spain's worst aviation disaster since 1983 were those who fell into a stream and avoided severe burning.

The government said only 19 people of the 166 passengers and six crew aboard survived the MD-82 jet crash.

There were 20 children and two babies among the dead.

Relatives gathered at an improvised morgue in a convention centre to identify the bodies, many of which were badly burned.

Development Minister Magdalena Alvarez said the condition of the bodies made identification very difficult.

Ms Alvarez said: "Those responsible say that it will take two days at the most to finish identifying people by their fingerprints. DNA identification will take a bit more."

A passenger list published by Spanair showed mostly Spanish names but the government said there were 11 nationalities on board including people from Sweden, Germany, the Netherlands and Chile.

Madrid's regional government declared three days' official mourning and people gathered at the central Plaza de Cibeles square for a minute's silence midday Thursday.

An official investigation into the crash is under way but is not expected to report for several months.

Ms Alvarez said the cause of the accident seemed to be "an error in take-off".

A source close to the situation said the plane's left engine, made by Pratt & Whitney, had caught fire.

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