Photo shows the wreckage of a bus after it fell into a valley near Miaoergou village in the Changji Hui autonomous prefecture, Xinjiang Uygur autonomous region, on June 18, 2013.  [Photo by Xinjiangnet.com.cn]

At least 15 people were killed after a bus with 36 passengers fell into a valley in Northwest China's Xinjiang Uygur autonomous region on Tuesday afternoon.

The accident happened at around 5:15 pm in an area with an average altitude of 2,000 meters near Miaoergou village, in the Changji Hui autonomous prefecture.

The passengers were employees of a local company who were returning after touring an attraction near the village, the Xinjiang information office said on Tuesday evening.

The bus, which was not overloaded, rolled over and fell about 40 meters into the valley. The road on which it was traveling was wet and muddy because it had rained during the day, the Changji public security bureau said. According to initial investigations, mist and poor visibility might be partly to blame for the accident.

Mist in the valley has also hampered rescue work, but all the passengers have been transferred to hospitals in Changji city, capital of the prefecture, police said.

Although the rain has stopped, the road on which the accident occurred remained slippery late on Tuesday night. The wreckage of the bus was still in the valley and authorities' investigations continued.

Contact the writers at maoweihua@chinadaily.com.cn and cuijia@chinadaily.com.cn