A bus overturned in a mountainous region of China's west, killing 25 students and their parents, state media said Wednesday. The bus was traveling on a remote highway in the restive western province of Xinjiang, the official Xinhua News Agency reported. It was about 1,180 kilometers from the regional capital of Urumqi when it flipped over. Most of the dead were students on their way to have health exams necessary for admission to high schools in China's more developed east, Xinhua said. Five injured people were being treated in a hospital, the agency said, citing an unnamed official at the regional emergency response office. Xinhua did not say what caused the accident, reporting only that it was under investigation.