A passenger coach crashed into the wall of an expressway tunnel in China's northwest, killing at least 36 people and injuring 13 others, official media reported on Friday. The injured were sent to the hospital and rescue efforts were ongoing. The accident occurred in Shaanxi province late on Thursday as the coach was on its way along the Xi'an-Hanzhong expressway to Luoyang, a city in central China, from Chengdu, the capital of the southwestern province of Sichuan, the Xinhua News Agency reported, citing the provincial police bureau. More details were not immediately available, and it wasn't clear if the coach was the only vehicle involved. Minister of Public Security Guo Shengkun ordered a swift investigation into the accident, according to state broadcaster China Central Television.