An express train traveling through strong winter winds derailed in northern Japan on Sunday, killing at least four people and injuring more than 30, a police official said.

One man remained trapped in the wreckage and appeared to be unconscious, the Yamagata prefectural police official said on condition of anonymity, citing departmental policy. The official said the man was believed to be the last person still inside.

The injuries of the survivors outside the wreckage did not appear to be life-threatening, Yamagata police spokesman Yoshikatsu Oe said.

Five cars of the six-car express train derailed at 7:20 PM, three of them toppling onto their sides in Yamagata prefecture, about 180 miles north of Tokyo, officials said. The train was going from northern Akita to Niigata prefecture.

It was unclear how many passengers were on the train, but Oe said most of the injured were on the first two cars.

After rescuing the last remaining person inside the train, rescuers planned to lift the wreckage to see if any other passengers were beneath, said the police official who spoke on condition of anonymity.

Railway operator JR East Co. President Mutsutake Otsuka apologized for the accident at a news conference Monday morning and promised a thorough investigation.

Transport Ministry official Hiromi Mishima said it was not known what caused the derailment and officials were assessing the extent of the damage.

Yamagata police official Yasuhiro Sugiu said there had been high-speed wind warnings for the area. NHK quoted a train conductor as saying a strong gust hit the train just before the accident. Winds in the area were about 48 mph, Kyodo reported.

Japan in recent days has suffered from unusually heavy snowfall, and blizzards have led to the deaths of eight people. But snow did not appear to be a factor in Sunday's crash. NHK footage showed the wreckage in a rural area with only patches of snow on the ground.

Authorities said they did not know how fast the train was going.

Speed was believed to be a factor in an April 25 train wreck that killed 107 people and injured more than 500 others in Amagasaki, western Japan. That accident was Japan's worst train wreck since 1963.

(Chinadaily.com via agencies December 26, 2005)