At least 15 people were killed when a tourist bus plunged 50 meters into a ravine in the northern Chinese province of Shanxi on Saturday, state media said. The accident happened at a section of the State Highway 207 in the county-level city of Gaoping, administered by Jincheng City, according to the provincial traffic police authorities. The 35-seat bus, carrying 33 people, was en route to Jiyuan City in central Henan Province from Jincheng, said the authorities. The bus is operated by the Transportation Corporation of Sanmenxia City in Henan, Chinese news agency (Xinhua) reported. Rescue efforts are underway. The cause of the accident is under investigation.