The deadly train derailment on Monday in Japan killed at least 49 people and left 239 others injured, and speeding might have led to the accident.

The death toll made itself the most serious in Japan since May 14, 1991, when 42 were killed and 527 others injured in a collision of two trains in west Japan.

The seven-carriage train with about 580 passengers aboard derailed at about 9:20 a.m.(0020 GMT) Monday in Amagasaki, Hyogo Prefecture.

Earlier reports said the train derailed after hitting a car at a railway crossing. However, the police said the train is likely to have derailed before hitting a car parked in a parking lot as there was no sign of impact on the tracks, according to Kyodo News.

The incident happened at a curve, and the train was about one and a half minutes behind schedule when it set out from the pervious station. The upper limit speed at the curve is 70 kilometers an hour, local press reports said.

Four of the seven carriages derailed, with the first two rammed into a building near the track.

Rescue works are now focused on the two carriages where some passengers are feared to be trapped. The driver, still trapped in the badly mangled carriages, was seriously wounded, Kyodo quoted rescuers as saying.

The central and local governments have set up headquarters and offices to gather information and deal with the accident.

All those trains in the two accidents belong to the West Japan Railway Co. and the company has made apology for Monday's accident.

Prime Minister Junichiro Koizumi has urged railway operators to take precautions against such accidents.

"They have to take precautions on a routine basis," he said. "I think it will take time to clear up the causes of it but we want solid measures to be taken to make sure this kind of incident never happens," Kyodo news quoted Koizumi as saying in his office.