URUMQI -- At least four passengers were killed and more than 30 injured in a train derailment in northwest China's Xinjiang Uygur Autonomous Region early Wednesday, rescuers said.

According to sources with the Urumqi Railway Bureau, 11 carriages of Train No. 5806 were derailed by a strong windstorm around 2:00 am, soon after it left the Turpan station. The train runs between Urumqi, capital of Xinjiang region, and Aksu, a city in southern Xinjiang.

The accident occurred between Zhenzhuquan station and Hongshanqu station, about 20 to 30 km away from Turpan.

The windstorm was observed to have a force of 13, which is more powerful than a hurricane, according to the railway bureau.

The railway south of the Tianshan Mountains from Turpan to Korla has been closed, said the railway bureau.

"A strong sand storm cracked window panes soon after the train left Turpan, and blrew some of the cars off the rail when we were trying to plugging up the windows," said a passenger named Su Chuanyi, a local TV journalist.

"The first rescue team of more than 100 people, including doctors and police officers, arrived by 4:30 a.m. They are now working at the scene," Su said.

The mishap occurred near a windmill farm 120 km away from Urumqi. The area is well known for strong winds all the year round.

The Zhenzhuquan station was attacked by a windstorm in April 2001, which derailed 11 cars of a train parked there.